
Glass. 
Book. 



^M£- 



Issued April TO. 1912. 



U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ANIMAL INDUSTRY.— Bulletin 144. 

A. D. MELVIN, Chief of Bureau. 



INVESTIGATIONS RELATIVE TO ARSENICAL DIPS AS 
REMEDIES FOR CATTLE TICKS. 



BY 

B. H. RANSOM, Ph. D., 

Chief of the Zoological Division, 
AND 

H. W. GRAYBILL, D. V. M., 

Assistant Zoologist. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1912. 



■on^npli. 



Issued April 10, 1912. 



U. S. DEPARTMENT OF AGRICULTURE, 

• BUREAU OF ANIMAL INDUSTRY.— Bulletin 144. 

A. D. MELVIN, Chief op Bureau. 



INVESTIGATIONS RELATIVE TO ARSENICAL DIPS AS 
REMEDIES FOR CAHLE TICKS. 



BY 

B. H. RANSOM, PH. D., 

Chief of the Zoological Division, 
AND 

H. W. GRAYBILL, D. V. M., 

Assistant Zoologist. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 

1912. 




^ 



"T^'e. 



THE BUREAU OF ANIMAL INDUSTRY. 



Chief: A. D. Melvin. 

Assistant Chief: A. M. Farrington. 

Chief Clerl: Charles C. Carroll. 

Animal Husbandry Division: George M. Rommel, chief. 
' Biochemic Division: M. Dorset, chief. 

Dairy Division: B. H. Rawl, chief. 

Inspection Division: Rice P. Steddom, chief; Morris Wooden, R. A. Ramsay, 
and Albert E. Behnke, associate chiefs. 

Pathological Division: John R. Mohler, chief. 

Quarantine Division: Richard W. Hickman, chief. 

Zoological Division: B. H. Ransom, chief. 

Experiment Station: E. C. Schroeder, superintendent. 

Editor: James M. Pickens. 

ZOOLOGICAL DIVISION. 

Chief: B. H. Ransom. 

Assistant Zoologists: Albert Hassall, Harry W. Graybill, Maurice C. Hall, 
and Howard Crawley. 

Junior Zoologist: Winthrop D. Foster. 

2 



x!x 






^ 



Vo 



LETTER OF TRANSMITTAL. 



U. S. Department of Agriculture, 

Bureau of Animal Industry, 
Washington, D. C, August 12, 1911. 

Sir: I have the honor to transmit, and to recommend for pubUca- 
tion in tlie bulletin series of this bureau, the manuscript of a paper 
entitled ''Investigations Relative to Arsenical Dips as Remedies for 
Cattle Ticks," by Drs. B. H. Ransom and H. W. Graybill, of the 
Zoological Division. 

One of the most important phases of the problem of dealing with 
the Texas fever tick is the finding of some effectual means of ridding 
cattle of the parasites. When large numbers of animals are concerned 
the most practical way of doing this is by dipping them in some sub- 
stance that will destroy the ticks. A large variety of dips have been 
tried in this and other countries, but it has been difficult to find one 
that will kill the ticks without causing more or less injury to the 
cattle harboring them. 

The experiments described in this bulletin indicate that arsenical 
dips, when properly compounded and used, furnish the best means yet 
devised for the purpose, as they are effective in destroying the ticks 
and at the same time least objectionable in their effects upon the 

cattle. 

Respectfully, A. D. Melvin, 

Chief of Bureau. 
Hon. James Wilson, 

Secretary of Agriculture. 

8 



CONTENTS. 



Pago. 

Introduction 7 

Composition of the dips used in the experimental work 9 

Details of the experiments 10 

Arsenic, soda, and pine-tar dips 10 

Arsenic, soda, and pine-tar dip containing emulsified crude petroleum. ... 33 

Arsenic and zinc-sulphate dip 34 

Arsenic-alum dip 36 

Sodium-arsenate dip 37 

Sodium-sulpharsenite dip 38 

Potassium-arsenite dip containing soap 38 

Effect of repeated applications of the arsenic, soda, and pine-tar dip 44 

Discussion of results 47 

Effects of arsenical dips on cattle 47 

Effects of arsenical dips on ticks 49 

Female ticks 51 

Male ticks 58 

Nymphs and larvae 59 

The protective action of arsenical dips 60 

Practical significance of results of experiments with arsenical dips 61 

Composition of the dip 61 

Method of application 62 

Number and frequency of applications 63 

Handling the cattle 64 

5 



ILLUSTRATIONS. 



PLATES. 

Page. 
Plate I. One hundred and twenty-three engorged female ticks after dipping 

in an arsenical solution 12 

II. One hundred and five engorged female ticks collected on the same 
date as those shown in Plate I and kept under the same conditions 
but not dipped 12 

III. Fig. 1. — Fifty-seven engorged and nearly engorged female ticks col- 

lected from a calf immediately after dipping in an arsenic and 
pine-tar solution. Fig. 2. — Seventeen engorged female ticks col- 
lected from an undipped calf 16 

IV. Fig. 1. — Seven fully engorged and 17 partially engorged female 

ticks collected from a calf the next day after dipping in an arsenic 
and pine-tar solution. Fig. 2. — Engorged female tick collected 

from an undipped caU IG 

V. Fig. 1. — Seven fully engorged and 10 partially engorged female 
ticks collected from a calf two days after dipping in an arsenic and 
pine-tar solution. Fig. 2. — Five fully engorged and three partially 

engorged female ticks collected from an undipped calf 18 

VI. Fig. 1.^ — Fifty-one engorged female ticks after dipping in an arsenic 
and pine-tar solution. Fig. 2.— Forty engorged female ticks col- 
lected from an undipped calf 18 

TEXT FIGURE. 

Fig. 1. Plan of draining pen for cattle after dipping (55 

6 



INVESTIGATIONS RELATIVE TO ARSENICAL DIPS AS 

REMEDIES FOR CAHLE TICKS. I 



INTRODUCTION. 

It is now a well-known fact that the Texas-fever tick may be 
eradicated from cattle and pastures by following a certain course of 
procedure in which the cattle are moved from time to time from 
one pasture to another; in other words, eradication may be accom- 
plished by so-called "rotation methods" without the necessity of 
treating the cattle with tick-killing substances. In many instances, 
however, it is impracticable, uneconomical, or on some other account 
undesirable to depend upon the automatic eradication which ulti- 
mately takes place when proper rotation methods are followed. 
Therefore it becomes necessary ill such cases either to use them in 
connection with other methods or to resort to other methods alone. 
The dipping or spraying of cattle with a substance destructive to 
ticks provides a means of hastenmg eradication and of rendering it 
possible in the presence of conditions under wdiich unmodified rota- 
tion methods would be practically out of the question. 

Ever since the fact that the tick is the agent of transmission of 
Texas fever was established, investigations have been carried on under 
the auspices of the Bureau of Animal Industry, State agricultural 
experiment stations, and other institutions for the purpose of dis- 
covering some substance which, when applied externally to the bodies 
of tick-infested cattle, would free them from ticks without injury to 
the animals themselves. Very early in the history of these investi- 
gations it was found that ticks were highly resistant to treatment, 
and it has been determined that several remedies which give good 
results in the case of such external parasites as mange mites and 
lice are of little or no use in the case of ticks. Some substances 
appeared to have absolutely no effect and others, when applied at a 
sufficient strength to destroy the ticks, were so severe in their effects 
upon the cattle that they could not be used in practice. For example, 
lime-and-sulphur, tobacco, and coal-tar dips, which are very satis- 
factory remedies against certain other external parasites of cattle, 
have been found to have no practical value in the destruction of ticks. 
Oil dips have proved more successful, and for several years crude 

7 



8 ARSENICAL DIPS FOR CATTLE TICKS. 

petroleum, provided it conformed to certain requirements as to its 
physical and chemical characteristics, has been recognized by the 
live-stock sanitary authorities of the Federal Government and of 
various States as an efficacious remedy against cattle ticks. How- 
ever, although the efficacy of crude petroleum is generally admitted, 
there are a number of more or less serious objections to it which have 
largely interfered with its usefulness. Among these objections may 
be mentioned the facts that in practice crude petroleum of proper 
composition is difficult to procure, is rather expensive, bulky, liable 
to loss by leakage, is frequently very severe in its effects upon cattle, 
and produces a greasy condition of the hair and skin which is highly 
undesirable in the case of dairy cattle. 

About six years ago the Bureau of Animal Industry began investi- 
gating arsenical solutions with reference to their utility for dipping 
cattle to free them from ticks. At that time arsenical dips as reme- 
dies against ticks had been considerably used in South Africa, and 
to some extent in Australia and South America, but practically not 
at all in the United States. In 1906, following the publication of 
two articles^ by Dr. N. S. Mayo, at that time chief veterinarian of 
Cuba, in which an arsenical solution was highly recommended as both 
efficacious against ticks and noninjurious to cattle, a number of trials 
of arsenical solutions were made in Texas, at first under cooperation 
between the Bureau of Animal Industry and the live-stock sanitary 
commission of Texas and later by the Bureau of Animal Industry 
working alone. The composition and method of preparing the 
arsenical solution as described by Mayo, in the first article referred to, 
are as follows : 

White arsenic 1| pounds. 

Sodium carbonate, crystals 4J pounds. 

Yellow soap 4J pounds. 

Pine tar 1 quart. 

Water 100 gallons. 

The arsenic is to be dissolved in 5 or more gallons of water by boiling for one-half 
hour; when dissolved add it to 20 gallons of water. Shave the soap, mix with the 
Boda and dissolve m 5 gallons of water. Wlien dissolved, add the tar in a fine stream 
and stir until the tar is in solution, then mix with the arsenical solution and add 
Bufficient water to make 100 gallons. 

In the second article referred to, which appeared about a month 
later. Mayo gave a somewhat different formula, but essentially the 
same method for preparing the arsenical dip, as follows: 

Arsenious acid 8 pounds. 

Soda carbonate, crystals 24 pounds. 

Yellow soap 24 pounds. 

Pine tar 1 gallon. 

Water 500 gallons, 

'Breeder's Gazette, vol. 4'J, No. 11, p. 564, and American Veterinary Review, vol. 30, No. 2, pp. 243-245. 



COMPOSITION OF DIPS, 9 

Dissolve the arsenic in 20 gallons or more of water by boiling for 30 to 40 minutes. 
When dissolved, add to 100 gallons of water. Dissolve the soap and soda in 20 gallons 
of boiling water, first shaving the soap, and while boiling add the pine tar in a thin 
stream and stir until it is dissolved. Mix this with the arsenical solution and add 
sufficient water to make 500 gallons. 

In the course of the first year's trials of the dip in Texas Dr. Mayo's 
formula was slightly modified by the omission of the soap, which did 
not seem to add to the efficacy of the dip. The formula and method 
of preparation which were usually employed were as follows: 

White arsenic 8 pounds. 

Sodium carbonate 24 pounds. 

Pine tar 1 gallon. 

Water sufficient to make 500 gallons. 

The arsenic and sodium carbonate were dissolved by boiling in 
25 or 30 gallons of water, after which the fire was drawn and the 
solution allowed to cool somewhat. The tar was then added, and 
finally the mixture was added to sufficient water to make 500 gallons 
of dip. 

During 1906 about 12,000 head of cattle were treated in Texas 
with the arsenical dip under the supervision of inspectors or agents 
of the Bureau of Animal Industry with results which in some respects 
were higlily encouraging. Though it appeared questionable from the 
reports of these dippings whether the dip was absolutely efficacious, 
there seemed to be no doubt as to its higlily destructive action on 
ticks and, as compared with crude petroleum, its slight injurious 
effects upon cattle. In fact, the apparent merits of the dip were 
such that its use was enthusiastically adopted by cattle owners in 
Texas and has been continued up to the present time, the range of 
popularity of the dip increasing from year to year. 

In consequence of the promising results secured in the first trials 
of the arsenical solution, the Bureau of Animal Industry has carried 
out a number of investigations and experiments in order to obtain 
definite data relative to the efficacy of arsenical solutions as remedies 
against ticks. 

COMPOSITION OF THE DIPS USED IN THE EXPERIMENTAL 

WORK. 

In most of the experiments the arsenical solution used was com- 
pounded in accordance with the modification of Dr. Mayo's formula 
given above, the amounts of arsenic varying from 8 to 12 pounds, and 
of sal soda from 24 to 45 pounds, for each 500 gallons of dip, in dif- 
ferent instances. When pine tar was used it was added in the pro- 
portion of 1 gallon to each 500 gallons of dip. In some of the experi- 
ments arsenical dips of somewhat different composition were used. 
The amount of arsenic in solution in the various dips, expressed in its 
equivalent of arsenic trioxid, varied from 0.16 to 0.495 per cent. 



10 ARSENICAL DIPS FOR CATTLE TICKS. 

In the Mayo dip and its modifications the arsenic is present in the 
form of a sodium salt loiown as sodium arsenite, which results from the 
chemical reaction which takes place between the arsenic (arsenic 
trioxid) and the sal soda (sodium carbonate) when these substances 
are boiled together. It has been found by Aubrey V. Fuller/ of the 
Biochemic Division of this bureau, that under certain conditions the 
sodium arsenite m an arsenical dip becomes more or less completely 
oxidized to sodium arsenate, this change occurring after the lapse of 
several weeks, a fact of great practical importance, since sodium 
arsenate seems to be weaker in its action upon ticks than is sodium 
arsenite. 

In the experiments recorded in the present paper the arsenic in the 
dips used was in solution as arsenite unless otherwise stated, and was 
known so to be either because the dips were used fresh or because the 
dips were afterwards proved by chemical analysis to be unoxidized. 

The proportionate amount of sal soda used in the arsenic, sal soda, 
and pine-tar mixture is more than is necessary to transform the arsenic 
into sodium arsenite. It has not been determined whether a dip con- 
taumig an excess of soda is more efficacious than one in which just 
enough soda has been used to complete the reaction with the arsenic. 
In view of the fact, however, that the cuticle of ticks is softened and 
may be dissolved by alkaline solutions, it is possible that the efficacy 
of the dip may depend in part upon the weak alkalinity given to it by 
the excess of soda used in its preparation. The function of the pine 
tar in the dip is indefinitely knowTi. Whether it actually renders the 
dip more efficacious is uncertain. It does, however, give body to the 
dip, and also serves the useful purpose of rendering the appearance 
and odor of the dip distinctive. 

DETAILS OF THE EXPERIMENTS. 

ARSENIC, SODA, AND PINE-TAR DIPS. 

Experiment No. 1. 

Twelve head of cattle, most of them moderately or heavily infested 
with ticks, were dipped October 13, 1907, near Quanah, Tex., in an 
arsenic, soda, pine-tar dip containing an equivalent of 0.204 per cent 
arsenic trioxid.^ The dip was prepared from 20 j^ounds of commercial 
arsenic (96.18 per cent arsenic trioxid^), 60 pounds of sal soda, 2 gallons 
of pine tar, and 1,075 gallons of water. The quantity of water was 
determined from arithmetical calculations based upon measurements 
of the dimensions of the vat. The vat was about 20 feet in length at 
the surface of the dip, and the cattle when dipped were immersed from 
5 to 10 seconds. 

1 Bureau of Animal Industry Circular 182. • * Analysis made in Biochemic Division. 



AKSENIC, SODA, AND PiNE-TAR DIPS. 11 

The cattle suffered no evident injury to the sldn as a result of dip- 
ping. Seven days after dipping they were nearly free from ticks, the 
ticks present being partially grown females, males, and nymphs. Of 
six engorged ticks which dropped from the cattle immediately after 
dipping, 4 died without depositing eggs, the other 2 depositing a few 
eggs, none of which hatched. Two days after dipping 14 engorged 
ticks were collected, 5 of which died without depositing eggs. The 
other 9 deposited a few eggs, none of which hatched. Eight engorged 
ticks collected October 12 from undipped cattle, and kept under the 
same conditions as those from the dipped cattle, all deposited a normal 
number of eggs, nearly all of which hatched. Four nymphs were col- 
lected two days after dipping. One afterwards molted, 1 died in 
course of molting, and 2 failed to molt. Seven days after dipping 13 
nymphs were collected. One of these afterwards molted, and 12 
failed to molt. Fourteen nymphs were collected from an undipped 
cow October 15 and kept under the same conditions as those from the 
dipped cattle. Ten of these afterwards molted, 1 died while molting, 
and 3 failed to molt. 

Ex'periment No. la. 

October 16, three days after the first dipping, a heavily infested cow 
was redipped, after the addition of 4 pounds of arsenic and 12 pounds 
of soda, previously boiled together, to the dip already in the vat. No 
analysis was made of this strengthened dip, but the amount of arsenic 
may be estimated as equivalent to about 0.24 per cent arsenic trioxid. 

October 20, four days after the second dipping and seven days after 
the first dipping, there was no apparent injury to the skin. Nearly 
all the ticks were dead. Those remaining alive were females one-half 
to fully grown, most of them showing distinct evidences of having been 
mjured by the dip. Twenty-five engorged ticks were collected from 
the cow in this experiment four days after the second dipping; 19 of 
these died within 24 hours; 2 of the remaining 6 afterward deposited 
a few eggs, none of which hatched. The other 4 died without deposit- 
ing eggs. Fourteen engorged ticks collected from undipped cattle 
October 22 and kept under the same conditions as those from the dipped 
cow deposited numerous eggs, most of which hatched. Another lot 
of 6 engorged ticks collected on the same date from undipped cattle 
deposited about 1,000 eggs, about 100 of which hatched. 

Experiment No. 2. 

Two cattle heavily infested with ticks were sprayed in a spraying 
machine October 22, 1907, near Vernon, Tex., with an arsenic, soda, 
and pine- tar dip containing an equivalent of 0. 172 per cent arsenic tri- 
oxid.^ The dip was prepared from 10 pounds of commercial arsenic 
(99.56 per cent arsenic trioxid 0, 24 pounds of sal soda, 1 gallon of 

1 Analysis made in Biochemlc Division. 



12 ARSENICAL DIPS FOR CATTLE TICKS. 

pine tar, and 500 gallons of water (measured in barrels). The cattle 
were held in the spraying machine for about 10 seconds. Owing to 
the faulty worldng of the machine, the application of the dip was not 
as thorough as it might have been had the machine worked properly. 
The skin injury as a result of spraying was very slight, and the 
evidences of injury had practically disappeared eight days after the 
treatment. Five days after spraying the skin of one of the animals 
was somewhat thickened between the hind legs and on the neck 
where the ticks had been numerous, and the skin on the neck of the 
other animal where the ticks had been particularly numerous was 
very slightly thickened and cracked. The cattle were nearly free 
from ticks eight days after spraying, the ticks present being partially 
grown females, males, and nymphs. Eight engorged ticks were 
collected from the cattle 16 hours after spraying. One of these died 
without depositmg eggs; the other 7 laid relatively few eggs, none of 
which hatched. Of 5 engorged ticks collected five days after spray- 
ing, 4 died without depositing eggs; the other one laid about 200 eggs, 
none of which hatched. Fourteen engorged ticks collected October 
22 from untreated cattle and kept under the same conditions as those 
from the sprayed cattle deposited numerous eggs, most of which 
hatched, and another lot of 6 engorged ticks collected on the same 
date from untreated cattle deposited about 1,000 eggs, about 100 of 
which hatched. Seven nymphs collected 16 hours after spraying 
failed to molt. Sixty-nine nymphs collected five days after spraying 
failed to molt. Seven nymphs collected eight days after spraying 
failed to molt. Twenty-five nymphs were removed from untreated 
cattle October 22 and were afterwards kept under the same conditions 
as those from the sprayed cattle. All but 4 of these molted. 

Experiment No. 3. 

Three cattle heavily infested with ticks and two cattle lightly 
infested were sprayed July 11, 1908, near Purcell, Okla., with an 
arsenic, sal soda, and pine-tar dip containing an equivalent of not 
more than 0.217 per cent arsenic trioxid. The dip was prepared from 
3 pounds of commercial arsenic (99.05 per cent arsenic trioxid 0, 
15 pounds of sal soda, 0.3 gallon of pine tar, and 165 gallons of water. 
The same spraying machine was used that was used in Experiment 
No. 2. The cattle were not held in the machine, but were allowed 
to pass through as rapidly as they would. 

The skin of these cattle was only very slightly injured. Five days 
after treatment 3 of the cattle were nearly free from ticks; the other 
2 could not be found on this date. The live ticks present w^ere 2 
engorged females, a few partially grown females, 1 male, and a con- 
siderable number of nymphs, which were apparently still alive. 

1 Analysis made in Biochemic Division. 



BuL. 144, Bureau of Animal Industry, U. S. Dept. of Agriculture. 



Plate I. 




Dipped Ticks. 

Experiment No. 4. One hundred and twenty-three engorged female ticks after dipping in an arsenical 
solution containing an eciuivalent of less than 0.22 per cent arsenic trioxid. The average weight of 
eggs per tick deposited by this lot (including all ticks whether they oviposited or not) was 23.4 
milligrams, and none of them hatched. Two-thirds natural size: from a photograph taken 24 days 
after dipping. Compare Plate II, showing untreated ticks collected on the same date as those shown 
in this plate. 



BuL. 144. Bureau of Animal Industrv, U. S. Dept. of Agriculture. 



Plate II. 




Undipped Ticks. 

Experiment No. 4. One hundred and five engorged female ticks collected on the same date as those 
shown in Plate I, and ki^|it inider the same conditions, but not dipped. The average weight of eggs 
per tick deposited l)v this lot (including all ticks whether they oviposited or not) was 127..5 milligrams, 
and practically all of them hatched. Two-thirds natural size; from a photograph taken on the same 
date as that of the ticks shown in Plate I. 



AKSENIC, SODA, AND PINE-TAR DIPS, 13 

Fifteen engorged females were removed from the cattle immediately 
after spraying. All of these died without depositing eggs. 

For comparison it may be noted, in the absence of any data as to 
engorged ticks from untreated cattle on July 11, that engorged ticks 
(number not recorded) collected July 11 from cattle sprayed July 8 
with an emulsion of crude petroleum and liquor cresolis compositus 
containing about 5 per cent crude petroleum and about 1 per cent 
cresylic acid, deposited a normal number of eggs, many of which 
hatched. These ticks were kept, after their removal from the cattle, 
under the same conditions as those from the cattle sprayed with the 
arsenical dip. Six nymphs were collected immediately after spraying 
from the cattle sprayed with arsenical dip, and 2 of these molted. 
Four nymphs were collected on the same date from the cattle sprayed 
three days before with the oil and cresol emulsion, and were kept after 
collection under the same conditions as those from the cattle sprayed 
with the arsenical dip; all but one of them molted. 

Experiment No. 4- 

August 7, 1908, 228 fully engorged ticks were collected from some 
infested cattle at the Bureau Experiment Station, Bethesda, Md. 
On August 8, 123 of these ticks were immersed in an arsenical solution 
containing an equivalent of not more than 0.213 per cent arsenic 
trioxid. They remained in the solution two minutes, were then 
removed and dried by means of filter paper, after which they were 
placed in a large Petri dish under a bell jar under which was also 
placed an open vessel of water. The arsenical solution was prepared 
from 1 gram of arsenic trioxid, 3 grams of sodium carbonate, and 
465 c. c. of water. No pine tar was added to the solution. Twenty- 
two of the ticks died without depositing eggs. The remainder 
deposited eggs whose aggregate weight equaled 2.876 grams. Ovi- 
position was completed September 1 (see PL I, from a photograph 
taken on this date). None of the eggs hatched. 

August 8 the remainder of the ticks collected the day before, 105 
in number, were placed in a Petri dish under the same bell jar as those 
which were immersed in arsenical solution and kept thereafter under 
the same conditions as the latter. All of the untreated ticks deposited 
eggs whose aggregate weight amounted to 13.394 grams, nearly 5 
times the weight of the eggs from the dipped ticks. ^ Oviposition was 
completed September 1 (see PL II, from a photograph taken on this 
date). Practically all of the eggs from the untreated ticks after- 
wards hatched. 

■ It is to be noted here and hereafter in this paper that when a comparison by weight is made between the 
eggs laid by ticks that have been dipped and the eggs in the corresponding control lot, the difference is 
somewhat emphasized, due to the fact that the eggs from dipped ticks commonly become more or less 
shriveled, and hence weigh somewhat less than the same number of normal eggs. 



14 ARSENICAL DIPS FOR CATTLE TICKS. 

Experiment No. 5. 

During several weeks in the late summer and early fall of the year 
1908, larval ticks were applied every other day to three calves at the 
Bureau Experiment Station, Bethesda, Md. On October 12 numer- 
ous ticks of all ages, from newly attached larvse to fully engorged 
females, were present on each of these animals. An arsenic, sal soda, 
and pine- tar dip was prepared which contained an equivalent of 0.16 
per cent arsenic trioxid.^ On the above-mentioned date one of the 
calves (No. 582) was dipped in the arsenical dip and was kept in the 
bath two minutes. After dipping this calf was placed in a non- 
infested pen. Beginning immediately after dipping, all female ticks^ 
so far as possible, were collected every day as they reached the stage 
of full engorgement. These ticks were brought to the laboratory 
and kept in Petri dishes. All but a very few of the ticks which 
matured were collected. Those which matured during the night of 
course escaped, except those found in the morning crawling on the 
floor of the pen. 

During the first week after dipping, October 12 to 18, inclusive, 
1,340 engorged ticks were collected from calf No. 582. The eggs of 
291 of these ticks, comprising some individuals from each day's 
collection, amounted in weight to 5.57 + grams, an average of 0.019 
gram per tick. Applying this average to the entire 1,340 ticks, the 
total weight of eggs may be assumed to be 25.46 grams. By calcula- 
tion from the records which were kept of the percentage of eggs 
hatching from the ticks of each day's collection, the eggs which 
hatched were found to correspond to a weight of 0.178 + gram, or 0.7 
per cent of all the eggs deposited by the ticks maturmg the first week 
'after dippmg, which corresponds to an average of 0.000133 gram per 
tick. Subsequent to October 18, ticks contmued to mature on calf 
No. 582 until November 9, four weeks after dipping, the total number 
maturing during this time being 67. 

Calf No. 583 was dipped October 12 in the arsenic, soda, and pine- 
tar dip after 0.5 per cent (by weight) glycerin was added. The period 
of immersion in the bath was 1^ minutes. After dipping, the calf was 
placed in a noninfested pen. The same procedure %\dth regard to the 
collection of engorged ticks was followed as in the case of the other 
calf. During the first week after dipping, from October 12 to 18, 
inclusive, 1,907 engorged ticks were collected from calf No. 583, and the 
eggs of 599 of these ticks amounted in weight to 10.2 4- grams, an 
average of 0.017 gram per tick. Assuming that each of the entire 
number (1,907) collected averaged the same amount of eggs deposited, 
the entire weight of eggs may be estimated at 32.4 + grams. The 
number hatching, as calculated from the records kept of the per- 

> Analysis made in Biocheinic Division. 



AKSENIC, SODA. AND PINE-TAR DIPS. 15 

centage which hatched from the ticks of each clay's collection, corre- 
sponds to a weight of 0.325 gram, which is 1 per cent of the total 
quantity of eggs laid, or an average of 0.00017 gram per tick. The 
last tick to mature on calf No. 583 was collected on November 7, up 
to which time and subsequent to October 18, 37 female ticks reached 
the engorged condition. 

Calf No. 584, the undipped animal, was put in a nonmfested pen 
October 12 and no more larvae placed on it. The ticks which matured 
were collected every day, and some of these were placed in Petri 
dishes and kept under the same conditions as the ticks from the 2 
dipped animals. October 12 to 18, inclusive, the number of engorged 
ticks collected from calf No. 584, of which a record was kept, was 968. 
The weight of the eggs deposited by 358 of these was 25.54 + grams, 
an average of 0.071 gram per tick. . This average is about four times 
greater than the averages of the ticks from the 2 dipped calves. 
On the basis of an average of 0.071 gram of eggs per tick the total 
number of eggs deposited by the recorded ticks collected from calf 
No. 584 October 12 to 18 may be estimated as correspondmg to a 
weight of 68.7 + grams. The number which hatched, as calculated 
from the records kept of the percentage which hatched from the ticks 
of each day's collection, corresponds to a weight of 55.59 grams, which 
is 80 per cent of the weight of the entire number of eggs deposited, or 
0.0568 gram per tick. 

Assuming 0.04 milligram to be the average weight of a single egg, 
the average number of larvas produced by each tick maturing on 
calf No. 584, the undipped animal, as calculated from the foregoing 
data, was 1,400, whereas the number of larvae produced by the ticks 
maturing on the other calves during the first week after dipping 
averaged, as determined by a similar calculation, only 3.2 for each 
tick maturing on calf No. 582 and 4.2 for each tick maturing on calf 
No. 583. Ticks continued to mature on calf No. 584 until November 
18, and during the period from October 19 to November 9 (the latter 
date being the last daj' on which any ticks matured on either of the 
dipped animals) 1,029 ticks were recorded as maturing on this animal, 
in comparison with which it should be noted that only 67 and 37 ticks, 
respectively, matured on the 2 dipped cattle subsequent to October 18. 

From the foregoing it is evident that the 2 dipped calves became 
almost free from ticks within a week after dipping, only 67 in one case 
and 37 in the other, which afterwards matured, bemg present at the 
end of this time, a marked contrast to the fact that more than 1,029 
ticks that afterwards matured were still present on the undipped calf 
a week after removal from further infestation. 

No injury to the skin from dipping was noted other than a very 
slight dandruff-like exfoliation. The addition of the glycerin to the 



16 AESENICAL DIPS FOR CATTLE TICKS. 

dip in which the second calf was dipped had no apparent effect on the 
action of the dip. 

Experiment No. 6. 

On August 13, 1909, a calf which had been artificially infested 
with ticks, and which at the time of dipping harbored ticks in all 
stages of development, was dipped at the Bureau Experiment Station 
in an arsenic, sal soda, and pine-tar dip containing an equivalent 
of 0.215 per cent arsenic trioxid.* The dip was prepared from 7 
pounds of arsenic trioxid, 21 pounds of sodium carbonate (crystal- 
lized), 0.7 gallon of pine tar, and about 350 gallons of water. The 
calf remained in the bath two minutes. After dipping, the calf was 
kept in a tick-infested pen until August 20, seven days after the 
first dipping, when it was redipped in the dip which had been left 
in the vat since the first dipping. The calf was kept in the bath 
two minutes at the second dipping, and then removed to a non- 
infested pen. Beginning immediately after the first dipping the 
female ticks were collected as they reached the engorged condition. 

The skin of the calf was very slightly affected by the dipping, 
became somewhat thickened in places on the neck and thighs, and 
some exfoliation occurred. Wlien the animal was discharged from 
the experiment September 9 the skin was in excellent condition, 
soft, pliable, and very sleek. 

Five days after the first dipping a few newly molted adult ticks 
and a few partially engorged females were found to be alive. The 
latter were abnormally swollen as a result of arsenical poisoning. 
Nymphs apparently alive were rather numerous. Seven days after 
the first dipping most of these were certainly dead. A few newly 
molted adults were found to be alive, and partially grown females, 
abnormally swollen, were still present. No live larvae were found 
on either the fifth or seventh day. Eight days after the first dipping 
no live ticks in any stage of development were found, nor were any 
found subsequently. 

August 13, immediately after dipping, 57 engorged and nearly 
engorged female ticks were collected from the calf, all but 18 of 
which died without depositing eggs. These 18 ticks deposited eggs 
whose aggregate weight amounted to 0.077 gram, and none of these 
hatched. (See PL III, fig. 1, from a photograph taken Aug. 31.) 
Later in the day, August 13, 27 engorged females were collected, 17 
of which died without depositing eggs. The other 10 deposited eggs 
aggregating 0.1008 gram in weight, none of which hatched. 

In comparison note that 17 engorged females collected August 13 
from an undipped calf and kept under the same conditions as those 
from the dipped calf all deposited eggs weighing 0.8953 gram, 97 

1 Analysis made ia Biochemic Division. 



BuL. 144, Bureau of Animal Industry, U. S. Dept. of Agriculture. 



Plate III. 




Fig. 1.— Dipped Ticks. 
Experiment No. 6. Fifty-seven engorged and nearly engorged female t icks collected from a calf immedi- 
ately after dipping in an arsenic and pine-tar solution containing an equivalent of 0.21.5 per cent arsenic 
trio.xid The average weight of eggs per tick deposited bv this lot (including all ticks whether they 
oviposited or not) was 1.3 milligrams, and none of them hatched. Natural size; from a photograph 
taken 18 days after collection. 




Fig. 2.— Undipped Ticks. 

Experiment No. 6. Seventeen engorged female ticks collected from an undipped calf on the same 
date as those shown in Fig. 1, and kept under the same conditions. The average weight of eggs per 
tick deposited bv this lot (including all ticks whether they oviposited or not) was o2. / milligrams, ana 
97 per cent of them hatched. Natural size; from a photograph taken 18 days after collection. 



BuL. 144, Bureau of Animal Industry, U. S. Dept. of Agriculture. 



Plate IV. 




Fig. 1.— Dipped Ticks. 

Experiment No. 6. Seven fully engorged and seventeen partially engorged female tickscollected from 
a calf the next day after dipping in an arsenic and pine-tar solution containing an equivalent of 0.21.5 
per cent arsenic trioxid. The average weight of eggs per tick de|iositcd hy this lot (including all ticks 
whether they oviposited or not) was 2.1 milligrams, and none of them hatched. Natural size; from 
a photograph taken 17 days after collection. 




Fig. 2.— Undipped Tick. 

Experiment No. 6. Collected from an undipped calf one day earlier than those shown in Fig. 1 , and kept 
under the same conditions. The weight of eggs deposited by this tick was 42.6 milligrams, and 40 per 
cent of them hatched. Natural size; from a photograph taken IS days after collection. 



ARSENIC, SODA, AND PINE-TAR DIPS. 17 

per cent of which hatched. (See PL III, fig. 2, from a photograph 
taken Aug. 31.) Note also that one engorged female collected 
August 13 from an undipped calf and kept under the same conditions 
as the ticks from the dipped calf deposited eggs weighing 0.0426 
gram, 40 per cent of which hatched. (See PI. IV, fig. 2, from a 
photograph taken Aug. 31.) 

August 14, 24 ticks were collected, 7 of which were fully engorged, 
the others partially engorged. Five of these laid eggs weighing 
0.0512 gram. The others died without laying eggs. None of the 
eggs hatched. (See PI. IV, fig. 1, from a photograph taken Aug. 
31.) No ticks were collected on this date from undipped cattle, 
but it may be noted that ticks, already referred to, which were col- 
lected from undipped cattle the day before and were kept under the 
same conditions as those from the dipped calf deposited numerous 
eggs, a large proportion of which hatched. (See PI. IV, fig. 2, and 
PL III, fig. 2, from photographs taken Aug. 31.) 

August 15, 17 ticks (7 fully engorged and 10 partially engorged) 
were collected. Thirteen of these died without laying eggs. The 
other 4 laid eggs aggregating 0.05 gram in weight, none of which 
hatched. (See PL V, fig. 1, from a photograph taken Aug. 31.) 
No ticks were collected from undipped cattle on this date, but the 
lot of ticks just discussed may be compared with a lot of 8 females 
(5 fully engorged and 3 partially engorged) collected from an un- 
dipped calf the following day, August 16. These were kept under 
the same conditions as the ticks from the dipped calf, and all of 
them deposited eggs aggregating 0.4686 gram in weight, 99 per cent 
of which hatched. (See PL V, fig. 2, from a photograph taken 
Aug. 31.) 

August 16, 9 ticks (5 fully engorged and 4 nearly engorged) were 
collected, 2 of which died without laying eggs. The other 7 laid 
eggs aggregating 0.1713 gram in weight, none of which hatched. 

In comparison note that 8 ticks (5 fully engorged and 3 partially 
engorged) collected from an undipped calf August 16 and kept under 
the same conditions as the ticks from the dipped calf, all deposited 
eggs weighing 0.4686 gram, 99 per cent of which hatched. 

August 17, four days after the first dipping and the last day on 
which any ticks matured on the calf in this experiment, 1 engorged 
female was collected. This tick deposited eggs weighing 0.056 gram, 
and 50 per cent of them hatched. A tick collected from an undipped 
calf on the same date, and kept under the same conditions as the 
ticks from the dipped calf, deposited eggs weighing 0.0715 gram, 
98 per cent of which hatched. 
10407°— Bull. 144-^12 2 



18 ARSENICAL DIPS FOR CATTLE TICKS. 

Experiment No. 7. 

August 17, 1909, 15 engorged ticks collected the day before from 
undipped cattle at the Bureau Experiment Station were immersed 
in some of the dip used in Experiment No, 6, which contained an 
equivalent of 0.215 per cent arsenic trioxid. The ticks remained in 
the dip two minutes, were then removed, dried on filter paper, placed 
in a Petri dish, and kept under observation in the laboratory. Two 
of these survived until August 30, but none laid any eggs. Eight 
engorged ticks, which were collected on the same day as the ticks 
just referred to and kept under the same conditions except that 
they were not dipped, all deposited eggs whose aggregate weight 
equaled 0.4686 gram. Ninety-nine per cent of these eggs hatched. 

August 27, another lot of ticks, consisting of 51 engorged females 
collected August 25, were dipped in some of the same dip and were 
handled and kept under the same conditions as those discussed in the 
preceding paragraph. All of these died without laying eggs. (See 
PI, VI, fig. 1, from a photograph taken Aug. 31.) Another lot of 40 
females, collected August 25 and kept under the same conditions 
except that they were not dipped, all deposited eggs w^hose aggre- 
gate weight amounted to 2.1371 grams, and 60 per cent of these 
eggs hatched. (See PL VI, fig. 2, from a photograph taken Aug. 31, 
before oviposition was entirely completed.) 

Experiment No. 8. 

On August 26, 1909, a tick-infested calf was dipped in the arsenical 
dip used in Experiment No. 6, which had remained in the vat at the 
Bureau Experiment Station since* August 13. This dip originally 
contained an equivalent of 0.215 per cent arsenic trioxid, but analy- 
sis of a sample taken September 2 showed an equivalent of 0.234 
per cent arsenic trioxid. It is assumed that the dip had meanwhile 
lost sufiicient water by evaporation to cause this increase in the 
percentage of arsenic. ^Vlien used August 26 the dip therefore con- 
tained an equivalent of between 0.215 and 0.234 per cent arsenic 
trioxid. 

The calf used in this experiment had been artificially infested with 
ticks by applying larvae every other day for several weeks prior to 
dipping. Wlien the animal was dipped numerous ticks in all stages 
of development were present. The period of immersion in the bath 
was two minutes. After dipping, the calf was put into a tick-infested 
inclosure, and larval ticks were applied every other day until Sep- 
tember 2, when a second dipping was given. Before the animal 
was dipped the second time about 50 gallons of water were added to 
the dip in the vat. Analysis of a sample taken from the vat after 
the addition of the water showed that it contained an equivalent of 



BuL. 144, Bureau of Animal Industry, U. S. Dept. of Agriculture. 



Plate V. 




Fig. 1 .—Dipped Ticks. 

Experiment No. 6. Seven fully engorged and ten partially engorged female ticks collected from 
a calf two days after dipping in an arsenic and pine-tar solution containing an etiuivalent of 0.215 
per cent arsenic trioxid. The average weight of eggs per tick deposited l)y this lot (including all ticks 
whether they oviposited or not) was 3 milligrams, and none of them hatched. Natural size; from a 
photograph "taken 10 days after collection. 




Fig. 2.— Undipped Ticks. 

Experiment No. 6. Five fully engorged and three partially engorged female tiek.s collected from an 
undipped calf one day later thau those shown in Fig. 1, aiid kept under the same conditions. The 
average weight of eggs per tic'k deposited by this lot (including all ticks whether they oviposited or 
not) was 5S.6 milligi-ams, and 99 per cent of them hatched. Natural size; from a photograph taken 
15 davs after collection. 



BUL. 144, Bureau of Animal Industry, U. S. Dept. of Agriculture. 



Plate Vl. 




Fig. 1 .—Dipped Ticks. 

Experiment No. 7. Fift y-one engorged female ticks after dipping in an arsenic and pine-tar solution 
containing an equivalent of ().'215 per cent arsenic trioxid. All of them died without depositing 
eggs. Natural size; from a photograph taken 4 days after dipping. 




Undipped Ticks. 



Experiment No. 7. Forty engorged female ticks collected from an undipped calf on the same date as 
those shown in Fig. 1, and kept under the same conditions, but not dipped. The average weight 
of eggs per tick deposited by this lot (including all ticks whether they oviposited or not) was 53.4 
milligrams, and GO per centof them hatched. Natural size; from a photograph taken on the same 
date as that of the ticks shown in Fig. 1. 



ARSENIC, SODA, AND PINE-TAR DIPS. 19 

0.196 per cent arsenic trioxid. The period of immersion at the second 
dipping was two minutes. After this dipping the calf was removed 
to a noninfested yard. August 28, two days after the first dipping, 
no injury to the skin was yet apparent. September 2 the skin was 
slightly sore on the escutcheon and on the vulva, near the tail. There 
was a slight exfoliation on the inner side of the forelegs. On Septem- 
ber 9, seven da3^s after the second dipping, there was noted a very 
slight exfoUation, and the skin was very slightly irritated on escutch- 
eon, inguinal region, axillse, inner side of forelegs, and around anus. 
A few days later all signs of sldn injury had disappeared. 

August 28, two days after the first dippmg, a considerable number 
of adult ticks in various stages of growth were alive, many of them, 
however, evidently affected by the arsenic. Some nymphs were 
apparently alive. No ticks matured subsequent to August 29, three 
days after the first dipping. September 2 no live ticks were found, 
except some nymphs which were apparently alive. September 9, 
one week after the second dipping, the calf was entirely free from 
ticks. 

August 26, immediately after the first dipping, 46 engorged female 
ticks were collected from the calf. All of these but one died without 
laying eggs. This one deposited about 30 eggs, none of which hatched. 
Later on the same day 6 engorged females were collected, 3 of which 
died without laying eggs. The other 3 laid eggs weighing 0.0874 
gram, none of which hatched. 

In comparison with the above it may be noted that 40 engorged 
females collected from an undipped calf August 25, and kept under 
the same conditions as those from the dipped calf, all deposited eggs 
which weighed in the aggregate 2.1371 grams, 60 per cent of which 
hatched. 

August 27, 32 engorged females wer^ collected from the dipped 
calf, all but 8 of which died without laying eggs. These 8 deposited 
eggs weighing 0.0407 gram, none of which hatched. 

August 28, 6 engorged females were collected, 4 of which deposited 
eggs weighing 0.1034 gram. None of these hatched. The other 2 
died without depositing eggs. 

August 29, three days after the first dipping, the last ticks to 
mature were collected. These were 9 in number. All but 1 of 
these died without ovipositing. This one laid about 75 eggs, none 
of which hatched. 

No ticks with which the above may be compared were collected 
from undipped cattle between August 25 and September 7. The 
data previously given relative to 40 ticks collected on August 25 
from an undipped calf should, however, be noted in comparison 
with the data relative to the ticks maturing on the dipped calf, and 



20 ARSENICAL DIPS FOB CATTLE TICKS. 

it may also be noted that 5 engorged females collected September 
7 from undipped cattle deposited numerous eggs, 98 per cent of which 
hatched. 

Experiment No. 9. 

Beginning September 8, 1909, 3 calves, Nos. 725, 731, and 735, 
were artificially infested with ticks at the Bureau Experiment Sta- 
tion by applying larvae every other day. October 22 ticks in all 
stages of development were present, but none of the 3 calves ex- 
hibited more than a moderate degree of infestation. A greater num- 
ber of ticks in the various younger stages than in the later adult stage 
were present. The 3 calves were dipped October 22 in an arsen- 
ical dip freshly prepared from 7 pounds of arsenic trioxid, 8 pounds 
of anhydrous sodium carbonate, 0.7 gallon of pine tar, and 350 gallons 
of water. The dip contained an equivalent of 0.225 per cent arsenic 
trioxid.^ 

Calf No. 725 was immersed in the bath 2 minutes, calf No. 731 
1 minute, and calf No. 735 30 seconds. After dipping the 3 calves 
were removed to a tick-free yard. 

October 30, eight days after dipping, no skin injury was apparent. 
November 6 a dandruff -like scurf was noted on various parts of the 
body, but a similar condition was noted on the neck and dewlap of 
another calf which had never been dipped. In this experiment the 
skin injury may therefore be put down as so slight as to be scarcely 
if at all perceptible. 

October 30, eight days after dipping, a very few live partially 
grown adults and a very few nymphs apparently alive were found 
on calf No. 725 (dipped 2 minutes); a few live, partially grown 
adults and a few nymphs apparently ahve on No. 731 (dipped 1 
minute) ; and on No. 735 (dipped 30 seconds) it was noted that 
partially grown females were present which were abnormally swollen 
from arsenical poisoning. No ticks matured on any of the three 
animals subsequent to October 26, four days after dipping. Novem- 
ber 6, two weeks after dipping, the three calves when finally examined 
were found to be entirely free from ticks. 

Twenty engorged females were removed from No. 725, October 22, 
immediately after dipping, 3 of which died without depositing eggs. 
The other 17 deposited eggs amounting in weight to 0.3273 gram, 
none of which hatched. From No. 731, immediately after dipping, 
October 22, 6 engorged females were removed, 2 of which survived 
to deposit eggs, which amounted in weight to 0.0262 gram. None of 
these hatched. From No. 735, October 22, immediately after dip- 
ping, 14 females were removed, all but 1 of which were fully engorged. 

1 Analysis made in Biocbemic Division. 



ARSENIC, SODA, AND PINE-TAR DIPS. 21 

Eleven of these survived to deposit eggs, whose weight amounted to 
0.1933 gram. None of these hatched. In comparison it may be 
noted that 6 engorged females, removed from an undipped calf Octo- 
ber 22 and kept under the same conditions as those from the dipped 
cattle, all deposited eggs which aggregated 0.2599 gram in weight 
and that 25 per cent of these hatched. 

October 23, 15 engorged ticks were collected from calves Nos, 731 
and 735, Twelve of these deposited eggs weighing 0.335 gram, none 
of which hatched. The other 3 died without ovipositing. Ten en- 
gorged females were collected from No. 725 on October 23, 4 of which 
survived to deposit eggs, the other 6 dying without ovipositing. The 
eggs which were laid aggregated 0.0515 gram in weight, and none of 
them hatched. Twelve engorged females collected from an undipped 
calf October 23 and kept under the same conditions as those from 
the dipped cattle all deposited eggs, which aggregated 0.4422 gram 
in weight. Ten per cent of these hatched. 

October 24, 3 engorged females were collected from No. 725. All 
of these deposited eggs which amounted in weight to 0.0574 gram, 
none of them hatching. From No. 731 on October 24 were collected 
1 fully engorged and 3 nearly engorged females. Two of these sur- 
vived to deposit eggs which amounted in weight to 0.0335 gram. 
None of the eggs hatched. Twenty-one fully engorged and 8 nearly 
engorged female ticks were collected from No. 735 on October 24. 
Seventeen of these survived to lay eggs, the other 12 dying without 
ovipositmg. The eggs laid amounted in weight to 0.2458 gram, and 
none of them hatched. 

In comparison with the foregoing it may be noted that 13 females 
collected from an undipped calf on October 24 and kept under the 
same conditions as those from the dipped cattle all deposited eggs 
which amounted in weight to 1.0794 grams. One per cent of these 
hatched. 

October 25, 4 engorged females were collected from No. 725, 1 of 
which survived to lay eggs, which weighed 0.0255 gram. None of 
these hatched. One small engorged female was collected from No. 
731 on October 25. This tick died after depositing a very few eggs, 
none of which hatched. Eight fully engorged and 3 nearly engorged 
females were collected from No. 735 on October 25. Three of these 
ticks survived to lay eggs, which amounted in weight to 0.0372 gram. 
None of the eggs hatched. It may be noted in comparison with the 
foregoing that of 18 engorged females collected October 25 from 
an undipped calf and kept under the same conditions as those from 
the dipped cattle, 17 deposited eggs which amounted in weight to 
0.5333 gram. Two per cent of these hatched. 

October 26, 1 engorged female was collected from No. 731. This 
tick deposited eggs weighing 0.0397 gram, none of which hatched. 



22 ARSENICAL DIPS FOR CATTLE TICKS. 

On the same date 4 females nearly engorged were collected from 
No. 735, all of which died without depositing eggs. Of 7 engorged 
females collected from an undipped calf October 26 and kept under 
the same conditions as those from the dipped cattle, all deposited 
eggs. These eggs amounted in weight to 0.3705 gram and 1 per cent 
of them hatched. 

No ticks matured on calf No. 725 subsequent to October 25, three 
days after dipping, and none matured on Nos. 731 and 735 sub- 
sequent to October 26, four days after dipping. 

Owing to the low relative humidity to which the eggs of the ticks 
were subjected in this experiment, and the consequent small per- 
centage of eggs hatching in the case of the ticks from undipped 
cattle used for comparison, the failure of eggs deposited by ticks 
from the dipped cattle to hatch is less strildng than in the other 
experiments. 

Experiment No. 10. 

November 10, 1909, eleven 3-year-old steers and one 4-year-old 
steer were dipped at Benjamin, Tex., in an arsenic, sal soda, and 
pine-tar dip containing an equivalent of 0.22 per cent arsenic tri- 
oxid.^ The dip was prepared from 70 pounds of commercial arsenic 
(99.2 per cent arsenic trioxid 0, 180 pounds of sal soda, 7 gallons 
of pine tar, and about 3,500 gallons of water. The vat used meas- 
ured 35 feet 8 inches in length at the surface of the dip. The cattle 
in entering slipped down a slide board and, plunging into the bath, 
were totally immersed for a moment, after w^hich they swam tlirough 
the vat to the other end, where they left the bath by walking up 
an incline, which led to the draining pen. Each animal was in the 
bath from 10 to 12 seconds. The cattle were ordinary grass-fed 
steers in rather poor flesh, but strong and healthy. At the time the 
experiment w^as begun they all showed a moderate infestation with 
ticks in all stages of development. 

The cattle w^ere dipped on the afternoon of November 10. They 
remained in the stockyards overnight, and the following morning 
were driven about 5 miles to a small pasture, said to be badly infested 
with ticks, where they remained until the morning of November 17. 

November 14, four days after dipping, each of the 12 cattle was 
examined. For this purpose they were placed one by one in a chute 
at the ranch where the cattle were pastured durmg the interval 
between dippings. The unusual gentleness of the cattle greatly 
facilitated this and the other examinations and handlmg to which 
they were subjected during the experiment. On animals Nos. 1, 4, 
and 6 a few live, fully engorged, partially engorged, and newly 
molted adult female ticks were found. All except the fully engorged 

1 Analysis made in Biochemic Division. 



AESENIC, SODA, AND PINE-TAR DIPS. 23 

ticks showed distinct evidence of the injurious effects of the dip; that 
is, they were unnaturally swollen and in some instances abnormal 
in color. On No. 12 slight exfoliation of the skin was evident at 
the root of the tail and on the escutcheon. One live engorged female 
and a few live ticks in stages just prior to and just after the second 
molt were found. Nos. 2 and 8 showed slight exfoliation of the 
slvin, and harbored live ticks in stages just prior to and after the 
second molt. On Nos. 3 and 7 live, newly molted adult ticks were 
found, together with a few partially engorged females which were 
abnormally swollen and in a dying condition. No. 10 had a few 
live ticks partially engorged, and showed a slight exfoliation and 
tenderness of the skin on the escutcheon where the ticks had been 
numerous. The skin on the dewlap was slightly thickened and sen- 
sitive. On No. 5 there were a few live, newly molted adult ticks 
and the skin of the animal was very slightly affected. On No. 9 
there was 1 fully engorged live tick, a number partially engorged, 
evidently poisoned by the dip, and a few live young adults. The 
skin of this animal showed a very slight exfoliation. On No. 11 
there were a few live ticks, some of them young adults and some 
nearly engorged; all more or less affected by the dip. The skin 
showed scarcely any evidence of having been affected by the dip. 
November 17, one week after the first dipping, the cattle were 
driven back to the stockyards at Benjamin, where they were again 
examined. For this purpose the cattle were placed in the chute 
leading to the dipping vat. The cattle that exhibited signs of sldn 
injury (i. e., slight irritation and exfoliation) November 14 showed 
similar signs at this examination. The animals presented the 
appearance of having gained in weight since dipping. No fully 
engorged females were found alive on these cattle November 17. 
On No. 1, some half-grown adult ticks were found to be alive, and 
there were some nymphs apparently alive. On No. 3 the only live 
ticks found were a few partially grown adults badly affected by arsen- 
ical poisoning. On No. 4 there were a few partially grown females 
alive but affected by the dip, and a few nymphs apparentl}-^ alive. 
On No. 5, 1 recently molted female, and 1 partially grown female, 
both aft'ected by the dip, were found alive, and there were present 
also some nymphs possibly alive. On No. 6, 1 newly molted male 
was found alive, and 1 nymph apparently dive. On No. 7 a small 
partially grown live female and a nymph apparently alive were 
found. One newly molted female affected by the dip was all that 
was found alive on No. 8. On No. 9 some newly molted adults were 
found alive and a very few nymphs apparently alive. No. 10 had 
a few partially grown female ticks, which were badly affected by the 
dip. On No. 11 only 1 tick was found alive, a female two-thirds 
grown, badly affected by the dip. No ticks were found on No. 12. 



24 ARSENICAL DTPS FOR CATTLE TICKS. 

November 17, between 10 and 3 o'clock, the cattle were redipped 
in the dip remaining in the vat from the first dipping. During the 
dipping one of the animals became lodged in the vat in consequence 
of which he and 5 others remained in the bath nearly 1 minute. 
The remaining 6 were in the vat from 10 to 12 seconds each. 

At 6 o'clock November 17 the 12 cattle were loaded into a stock 
car, partitioned in such a manner that they were confined to a little 
more than one-half the interior space of the car. This car was one 
which had been disinfected at Kansas City October 21 under super- 
vision of a bureau inspector. It was further disinfected, before 
loading the cattle, by cleaning out all litter, sand, and dirt, and 
spraying with an arsenical solution of twice the strength of that used 
in dipping. At 8.20 p. m. the car of cattle left Benjamin in a local 
freight train, which arrived at Hamlm, Tex., about 55 miles distant, 
at 9.30 a. m. November 18. The cattle remained in the car at 
Hamlin and were brought back to Benjamin by a train which left 
Hamlin in the afternoon of November 18, and arrived in Benjamin 
about 1.30 a. m. November 19. The total period the cattle spent 
on the car was therefore about 31 hours. They were supplied with 
hay during this time, but not watered. At Benjamin they were un- 
loaded into a pen at the railroad stockyards which had been thor- 
ouglily cleaned and disinfected by scraping off the surface earth 
with a team and scraper, scraping away also the surface of the earth 
from a strip about 3 feet wide all around the outside of the fence, 
and by spraying all the woodwork inside and out with the double- 
strength arsenical solution as used in the disinfection of the car; 
finally the ground along the fence mside and outside w^as soaked with 
the double-strength arsenical solution. When seen on the morning 
of November 19 the cattle appeared to be in good condition. Begin- 
ning on this date they were fed Johnson-grass hay and a cottonseed 
product from a local mill. 

On November 22, five days after the second dipping, the cattle 
were examined individually, each animal being tied for examination 
against the fence by means of ropes attached to the horns and one hind 
foot. Each animal showed evidence of slight epithelial desquama- 
tion — in some instances very slight— exhibited in the form of a 
dandruff in the hair on the neck and at the root of the tail. This 
was the only skin injury evident. No live ticks were found on any 
of the animals except No. 8. In the case of this animal there was a 
partially grown female on the escutcheon abnormally swollen from 
arsenical poisoning, and a nymph near the root of the tail which was 
doubtfully alive. 

November 24 these two ticks were still present on No. 8. The 
nymph appeared slightly shriveled. November 25 the tick was gone 



ARSENIC, SODA, AND PINE-TAR DIPS. 25 

from the escutcheon and the nymph was still present but was dried 
and sliriveled and certainly dead. 

December 1, two weeks after the second dipping and three weeks 
after the fu-st dipping, the cattle were again thoroughly examined 
as on November 22. More or less dandruff-like scurf from the skin 
was still present in the hair. The odor of pine tar, which was rather 
marked at previous examinations, had nearly disappeared. Many 
of the warbles with which all of the animals were more or less infested 
were examined and most of them proved to be alive. It is therefore 
evident that the arsenical dip has little effect on these parasites. 
No live ticks were found on any of the animals except one female near 
the root of the tail on No. 12. This tick was about one-sixth grown 
and was badly swollen from arsenical poisoning. Evidently this 
tick was one which had been overlooked at previous examinations. 
It no doubt passed through the first dipping and probably through 
the second as a nymph. During the examination it became detached, 
which prevented the possibility of determining its ultimate fate if it 
had remained on the animal. It was, however, so loosely attached 
that it could not have retained its hold much longer, and even if it 
had it was so badly affected by the dip that it is safe to say, in view 
of the history of ticks in a similar condition in other experiments, that 
it had no chance of ever reaching fertile maturity. 

With reference to the weather conditions during the Benjamin 
experiments it may be noted (assuming that the records of the 
Weather Bureau station at Abilene, 80 miles distant, are applicable) 
that the only frost recorded was a killing frost on November 17, the 
day of the second dipping, and that this frost was the first of the 
season. The minimum temperature was 32° F., and this was recorded 
on November 17. The maximum temperature during the month of 
November was 84° F., recorded on the 5th, five days before the first 
dipping. The average daily maximum temperature during Novem- 
ber was 71.6°, and the average daily minimum 50.1° F. Beginning 
November 10 the weather was clear on 5 days, cloudy on 5 days, 
and partly cloudy on 11 days. The average daily cloudiness for the 
month was 4.9 (Weather Bureau scale). On November 13, three 
days after the first dipping, 0.56 mch of rain fell between 11.10 a. m. 
and 2.40 p. m. On November 15 during the night 0.04 inch of rain 
fell. There was no further precipitation until November 28, when it 
began raining at 10.40 a. m., continuing until some {ime during the 
night, beginning again at 2.50 p. m., November 29, and ceasing at 
9.40 p. m., the rainfall being 0.93 inch. 

On the whole the weather was favorable to the experiment. No 
previous frost and an average temperature of 60° F. during the 
period between the two dippings when the cattle were on a pasture said 
to be tick-infested were circumstances favoring reinfection subsequent 



26 AESENICAL DIPS FOR CATTLE TICKS. 

to the first dipping. The occurrence of rain three and five days after 
the first dipping, if it had any influence on the results of the dipping, 
would have tended to dimmish the efl^ectiveness of the treatment by 
washing off some of the arsenic which it may be assumed was left on 
the bodies of the cattle after dipping. 

The cattle were released and the Benjamin experiment was closed 
after the examination December 1. 

Experiment No. 11. 

September 23, 1910, 16 engorged female ticks collected September 
20, 1910, from infested cattle at the Bureau Experiment Station, 
were immersed two minutes in an arsenical dip taken from the vat 
at the station, were dried on filter paper, then placed in a Petri dish 
and kept under observation in the laboratory. The dip was prepared 
June 23 from 7 pounds arsenic trioxid, 6J pounds sodium carbonate 
(anhydrous), 0.7 gallon of pine tar, and 350 gallons of water, and 
remained in the vat all summer, cattle being dipped in it from time 
to time. Samples taken June 23 and July 14 showed an equivalent, 
respectively, of 0.217 per cent and 0.218 per cent arsenic trioxid m 
solution. ^ A sample taken September 15 showed in solution sodium 
arsenite equivalent to about 0.04 per cent arsenic trioxid, and total 
arsenic in solution equivalent to 0.217 per cent arsenic trioxid. ^ 
Therefore, in the dip when used in this experiment, although the total 
arsenic in solution was the same as when the dip was made, con- 
siderable oxidation - of the sodium arsenite had taken place. 

A second lot of 16 engorged ticks collected September 20 from sta- 
tion cattle were dipped two minutes, September 23, in a freslily made 
arsenical dip (10 grams arsenic trioxid, 25 grams sodium carbonate 
(crystallized), 8 c. c. pine tar, and sufficient water to make 4,150 
c. c), wliich it may be assumed contained sodium arsenite equivalent 
to about 0.24 per cent arsenic trioxid. 

Another lot of 16 engorged ticks collected September 20 were kept 
without dipping under conditions similar to the two lots which were 
dipped. 

Two of the ticks in the lot dipped in the oxidized dip deposited a 
few eggs, none of wdiich hatched. The other 14 died without ovi- 
positing. One of the ticks dipped in the fresh dip deposited about a 
dozen eggs, none of which hatched. The others died without ovi- 
positing. All of the 16 ticks which were not dipped deposited eggs, 
and of these 40 per cent hatched. 

Tliis experiment was repeated, using a second series of 2 lots of 
engorged ticks, 15 in each lot, collected September 22. One of these 

1 Analysis made in Biochemic Division. 

2 For a discussion of the oxidation of arsenical dips see a paper by Aubrey V. Fuller, of tlie Biochemic 
Division, entitled "The Spontaneous Oxidation of Arsenical Dipping Fluids," published as Bureau of 
Animal Induslry Circular 1S2. 



ARSENIC, SODA, AND PiNE-TAR DIPS. 27 

lots was dipped September 23 in the oxidized dip and the other in 
the freshly made dip. Nine of the ticks dipped in the oxidized dip 
deposited a few eggs, none of which hatched, the other 6 dymg with- 
out ovipositing. All of the ticks dipped in the fresh dip died without 
ovipositing. 

September 26, 66 engorged ticks were collected from undipped cat- 
tle, and on September 28 two lots of 22 each were dipped 2 minutes in 
the same dips that were used before. A third lot of 22 was kept under 
observation undipped. Three of the ticks dipped in the oxidized dip 
deposited a few eggs, none of which hatched, the remaining 19 dying 
without ovipositing. All of the 22 ticks dipped in the fresh dip died 
without ovipositing. Of the 22 undipped ticks, all but one deposited 
eggs, and 25 per cent of the eggs hatched. 

In the case of a fourth series of ticks, 2 lots of 21 each were collected 
October 3. October 4, 1 lot was dipped in the arsenical dip which 
was freshly made September 23. The other lot was kept under ob- 
servation undipped. Of the former lot, 3 deposited a few eggs, none 
of which hatched, the remaining 19 ticks dying without ovipositing. 
All of the ticks of the second lot, except one, deposited eggs, and 75 
per cent of the eggs hatched. 

The rather low percentage of hatching among the eggs deposited 
by the undipped ticks was due to the low relative humidity of the 
air of the room, where the ticks and eggs were kept during the experi- 
ments, and it is possible that some of the eggs deposited by the dipped 
ticks might have hatched had the conditions as to moisture been more 

favorable. 

Experiment No. 12. 

During the summer and fall for several weeks prior to October 10, 
1910, 7 young cattle at the Bureau Experiment Station were artifi- 
cially infested with ticks by applying larvae every few days. On the 
date named 6 of them were sprayed with arsenical solutions by means 
of a hand spray pump. Three different solutions were used, and 2 
cattle were sprayed with each solution. The seventh animal was 
reserved untreated as a control. All of the cattle were kept after 
dipping in the pen which they had occupied prior to the treatment, 
and four days after spraying larval ticks were applied to each animal. 

Lot A. — The two cattle in this lot were sprayed with the oxidized 
dip referred to in Experiment No. 11. A sample taken from the vat 
October 20 showed that oxidation of the arsenic had continued since 
the taking of the previous sample, September 15, the amount of 
sodiiun arsenite present having been reduced to the equivalent of 
about 0.02 per cent arsenic trioxid/ though the total arsenic in solu- 
tion was the same as before. 

J Analysis made in Biochemic DivisioQ. 



28 ARSENICAL DIPS FOR CATTLE TICKS. 

At the time of spraying one of the cattle was sHghtly infested, the 
other moderately infested with ticks in all stages of development. 
Three days later the cattle were examined. One of them showed a 
slight exfoliation of the skin on the dewlap ; on the other the skin was 
unaffected. On one animal a few live nymphs and adidts, some of 
the latter engorged females, were found. On the other there were live 
ticks in various stages, mostly nymphs, but some engorged females 
apparently in good condition were noted. 

Ten days after the spraying one of the cattle showed exfoliation of 
the epidermis on the crest of the neck and withers, and on the dewlap, 
very slight in the latter location. Very slight exfoliation confined 
almost entirely to the dewlap was noted in the case of the other ani- 
mal. On one of the cattle a live larva nearly ready to molt was 
found, also several live males, and females which had evidently molted 
a few days before the examination. On the other there were 5 
apparently healthy engorged females with live males, and a dozen or 
more newly molted females, all more or less affected by the dip. 

October 20, 10 days after the first spraying, the cattle were again 
sprayed with some of the same dip as before. 

Four days later the cattle were examined. Slight exfoliation of 
the epidermis was found as before. On one a recently molted female 
and a male were found alive, on the other an engorged female and a 
recently molted female and 2 males. 

Seven days after the second spraying the skin injury was still very 
slight. A half-grown adult female and a male on one animal and a 
two-thirds grown aduH female on the other animal were the only live 
ticks found. 

Eleven days after the second spraying one of the cattle showed a 
hard granular exfoliation of the skin on the withers ; the other showed 
no signs of skin injury. No ticks were found on one. On the other 
there was an engorged female, 2 adult females one-fourth grown, and 
3 males. 

Fourteen days after the second spraying the exfoliation of the epi- 
dermis on the withers was still noticeable in the case of one of the 
cattle. No ticks were found on this animal. On the other a par- 
tially engorged female and a nymph were found to be alive. 

Twenty-one days after the second spraying the last examination 
was made. There were no longer any signs of sldn injury. One of 
the animals was free from ticks; the other had several partially grown 
adult females on the belly, some of them newly molted. 

So far as possible all of the engorged females were collected as they 
matured on the treated animals, beginning immediately after the 
first spraying. These were brought to the laboratory and kept under 
observation in Petri dishes. For comparison engorged and partially 
engoro;ed ticks were collected from time to time from the untreated 



AKSENIC, SODA, AND PINE-TAR DIPS. 29 

animal which served as a control and these were kept under the same 
conditions as those from the sprayed cattle. 

Immediately after the first spraying 11 engorged ticks were col- 
lected from one of the sprayed cattle and 3 from the other. Three 
of the former died without ovipositing, and 8 deposited eggs, none of 
which, however, hatched. All 8 of the ticks from the other animal 
deposited eggs, and 5 per cent hatched. 

For comparison it may be noted that all of 29 ticks collected on the 
same date from the untreated animal deposited eggs, and that 40 per 
cent of them hatched. 

One day after spraying 29 ticks were collected from one of the 
treated animals, 25 of which deposited eggs. None of the eggs 
hatched. Forty-five ticks collected the same day from the untreated 
animal all deposited eggs, 75 per cent of which hatched. 

Two days after spraying 8 ticks were collected from one of the 
treated animals, and 7 of these deposited eggs, but none hatched. 
All of 14 ticks collected the same day from the untreated animal 
deposited eggs, of which 4 per cent hatched. 

Three days after spraying 8 ticks were collected from one of the 
treated animals. All deposited eggs, but none of them hatched. 
All of 8 ticks collected from the unsprayed animal on the same date 
deposited eggs, but less than 1 per cent hatched. 

Four days after spraying 1 tick was collected from one of the 
spra^^ed cattle. This tick deposited eggs, but none hatched. On the 
same date 2 ticks were collected from the untreated animal. Both 
deposited eggs, but none hatched. 

No ticks were collected from the treated cattle for observation later 
than four days after the first spraying. 

Lot B. — The two cattle of this lot were sprayed with an arsenical 
dip freshly made from 91 grams of arsenic trioxid, 84 grams of 
sodium carbonate (anhydrous), 75 c. c. of pine tar, and 10 gallons 
of water. Analysis * showed an equivalent of 0.234 per cent arsenic 
trioxid in solution. One of the animals when sprayed was rather 
heavily infested, the other lightly infested with ticks in all stages of 
development. 

Three days after spraying no injury to the skin was noted. On one 
of the animals were noted numerous live ticks, nymphs and adults, 
some of the latter engorged, others partially grown and abnormally 
swollen from the effects of the dip. On the other there were a few 
live nymphs and some engorged ticks. 

Ten days after spraying one of the cattle showed a very slight 
exfoliation of the epidermis on the crest and side of neck, and an 
exfoliation at the base of the tail and tliickening of the skin in the 
anal region. On the other animal there was a slight exfoliation at 

1 Made in Biochemic Division. 



30 ARSENICAL, DIPS FOR CATTLE TICKS. 

the base of the tail and in front of the right shoulder. No hve ticks 
were found on one. On the other several nymphs were noted on the 
escutcheon as possibly alive, and a cluster of live ticks of various 
stages from young nymphs to engorged females was found on the 
inner side of the flank. 

Ten days after the first spraying the two cattle in this experiment 
were sprayed again with an arsenical dip freshly prepared from 7 
pounds arsenic trioxid, 6^ pounds sodium carbonate (anhydrous), 
0.7 gallon pine tar, and 350 gallons of water, containing an equiva- 
lent of 0.22 per cent of arsenic trioxid.^ 

Four clays after the second spraying an exfoUation of the epidermis 
on the brisket, right shoulder, and at the root of the tail was noted on 
one animal, and an exfoliation at the root of the tail and in the sacral 
region was observed on the other animal. No ticks were found on 
one. Alive nymph and a recently molted female were found on the 
other in the right inguinal region. 

Seven days after the second spraying the exfoliation of the skin 
was still slightly noticeable. No ticks were found on one animal. 
On the other the same 2 ticks noted at the previous examination were 
found, namely, a nymph and a female. 

Eleven days after the second spraying one of the animals showed 
no signs of epidermal exfoliation. , Slight exfoliation was still evident 
in the case of the other. On the animal which showed tick infesta- 
tion at the two preceding examinations a young female, a male, and 
a nymph were found alive in the right inguinal region. A female 
one-sixth gro-wn and a male were found on the other animal, whose 
presence was evidently overlooked at the preceding examination. 

Fourteen days after the second spraying the evidences of skin 
injury were still shght. No ticks were found on one of the animals, 
the female one-sixth grown and the male noted at the preceding 
examination having disappeared. A partiall}^ grown female, a male, 
and a newly molted female were found in the right inguinal region of 
the other animal, evidently the same ticks noted at the preceding 
examination. 

Twenty-one days after the second spraying when the final exami- 
nation was made no ticks were found on either animal. One of the 
animals still presented a slight epidermal exfoliation at the root of the 
tail, sides of hocks, and on the escutcheon. 

The same procedure with reference to the removal of ticks for 
further observation was followed as in the case of Lot A. 

Thirty-seven ticks were removed from one animal and 2 ticks from 
the other immediately after the first spraying. Of the former, 6 
deposited a very few eggs and none of these hatched, the other 31 
dying without depositing eggs. Both of the ticks from the other 

1 Analysis made in Biochemic Division. 



AKSENIC, SODA, AND PINE-TAR DIPS. 31 

animal deposited eggs, none of which hatched. For comparison it 
may be noted that 29 ticks collected at the same time from the 
untreated animal (already referred to under Lot A) all deposited 
eggs, of which 40 per cent hatched. 

One day after spraying 31 ticks were collected from the sprayed 
cattle, 18 of which deposited eggs. None of the eggs hatched. All 
of the 45 ticks collected on the same day from the untreated animal 
(as noted under Lot A) deposited eggs, of which 75 per cent hatched. 

Two days after spra^dng 12 ticks were collected from the sprayed 
cattle, 6 of which oviposited. None of the eggs hatched. The 14 
ticks collected from the untreated animal on the same day all depos- 
ited eggs, of which 4 per cent hatched. 

Three days after spraying 4 ticks were collected from the sprayed 
cattle. Two of these deposited eggs, but none hatched. All of the 
ticks, 8 in number, collected from the untreated animal on the same 
day, deposited eggs. Of these less than 1 per cent hatched, however. 

No ticks were collected from the cattle in this lot after the third 
day subsequent to the first spraying. 

The same remarks concerning the effects of the low relative humid- 
ity on the eggs of the ticks apply in the case of this lot as in the case 
of Lot A. 

Lot C. — The two cattle of this lot were sprayed with a special 
arsenical dip devised by Mr. Chapin of the Biochemic Division, bear- 
ing the laboratory designation of Tick Dip B. It contained potas- 
sium arsenite, pine tar, and some soap. The amount of arsenic in 
solution in a sample of the dip as diluted for use was equivalent to 
0.222 per cent arsenic trioxid.^ Both of the cattle sprayed with this 
dip were rather heavily infested with ticks in all stages of develop- 
ment. 

Three days after spraying a slight epidermal exfoliation on the 
dewlap and at the root of the tail was noted on one of the animals, 
and a slight exfoliation on the escutcheon where the ticks had been 
numerous was noted on the other animal. On one animal numerous 
Uve nj^mphs and adults, some engorged, were observed. Many of the 
adult ticks were abnormally swollen. On the other animal were 
observed partially grown adult ticks, alive, but mostly abnormally 
swollen and dark in color. Some nymphs apparently in good condi- 
tion were also seen. 

Ten days after spraying one of the cattle showed a slight epidermal 
exfoliation on the crest of the neck, on the shoulders, and on the 
brisket, and a slight scurf on the side of the neck. The skin of the 
dewlap was thickened and exfoliating. There was some exfoliation 
at the base of the tail, on the escutcheon, and inner side of thighs, 
with thickening of the skin. There was some exfoliation with slight 

1 Analysis made in Biochemic Division. 



32 ARSENICAL DIPS FOB CATTLE TICKS. 

soreness of the skin on the belly opposite the flank. The other animal 
showed similar skin conditions, but to a less degree. On the former 
there was a larva apparently alive located near the root of the tail. 
No live ticks were found on the other. Dead ticks were numerous on 
both animals. 

Ten days after the first spraying the cattle were sprayed again 
with Tick Dip B used at the same dilution as before. No analysis 
was made of the dip used at the second spraying. It is assumed, 
however, that the percentage of arsenic in the dip was the same 
as at the first spraying. 

Four days after the second spraying the evidences of skin injury 
were less marked than at the preceding examination. No live ticks 
were found- on either animal. 

Seven days after the second spraying exfoliation and thickening of 
the skin were still noticeable. No live ticks were found on either 
animal. 

Eleven days after the second spraying slight exfoliation of the skin 
in the anal region and on the escutcheon with considerable thickening 
in the latter location were noted on one animal. On the other the 
edge of the dewlap was dry and hard, and there was some exfoliation 
on the root of the tail. No ticks were found on either animal. 

Fourteen days after the second spraying slight evidences of the 
effects of the dip on the skin were still present. No ticks were found 
on either animal. 

Twenty-one days after the second spraying the evidences of skin 
injury were still noticeable. No ticks were found on either animal. 

The following observations were made on ticks removed from the 
cattle after spraying and kept in the laboratory: 

Immediately after the first spraying 59 ticks were removed from 
one of the cattle and 18 from the other. All died wdthout depositing 
eggs. In comparison it may be noted that 29 ticks removed from 
the unsprayed animal on the same day all deposited eggs, of which 40 
per cent hatched. 

One day after spraying 15 ticks were collected from the sprayed 
cattle. Seven of the ticks deposited eggs, of wliich none hatched. 
The 45 ticks removed on the same day from the unsprayed animal all 
deposited eggs, of which 75 per cent hatched. 

Two days after spraying 6 ticks were collected from one of the 
sprayed cattle. Three of these deposited eggs, none of which hatched. 
Fourteen ticks collected the same day from the unsprayed animal all 
deposited eggs, of which 4 per cent hatched. 

No engorged ticks were collected from the sprayed cattle later than 
two days after spraying. 

Notes on the untreated animal. — On the day the cattle in this 
experiment were sprayed the second time the untreated animal 



DIP CONTAINING EMULSIFIED PETROLEUM. 33 

exhibited a slight epidermal exfoliation on* various parts of the 
body. Ticks in all stages of development were numerous. 

Four days after the second spraying of the rest of the cattle the 
untreated animal showed a slight scurfiness of the sldn in various 
places. Ticks were still numerous, especially on the escutcheon. 

Seven days after the second spraying of the rest of the cattle 
numerous ticks in all stages of development, most abundant on the 
escutcheon, were noted on the untreated animal. 

Eleven days after the second spraying of the rest of the cattle the 
presence of nymphs and adidt ticks, abundant on the escutcheon 
and lower part of dewlap, was noted on the untreated animal. 

Fourteen days after the date of the second spraying a few nymphs 
and numerous adults were noted on the unsprayed animal. 

Twenty-one days after the date of the second spraying numerous 
adult ticks in various stages of growth were present on the unsprayed 
animal. One nymph was found at this time. 

ARSENIC, SODA, AND PINE-TAR DIP CONTAINING EIIULSIFIED CRUDE 

PETROLEUM. 

Experiment No. 13. 

Fifty gallons of crude petroleum mixed with 12^ gallons of hot 
concentrated soap solution were added to the arsenic, soda, and pine- 
tar dip used in experiment No. 2. A fairly good emidsion was 
obtained. No analysis of this dip was made, but it may be estimated 
that it contained about 10 per cent of crude petroleum and an equiva- 
lent of somewhat less than 0.172 per cent arsenic trioxid. October 22, 
4 cattle w^ere sprayed with this mixture in the same machine as used 
in experiment No. 2. The machine did not work properly during the 
spraying of these animals. October 23, 57 cattle were sprayed. The 
macliine worked well and these animals received a thorough spraying. 
On both dates the cattle were held in the machine at least 10 seconds 
each. Most of them were grossly mfested with ticks in all stages of 
development. 

Many of the cattle were rather severely injured by the treatment, 
the sldn becoming thickened, cracked, chafed, and sore to the touch, 
with exfoliation, and the animals showed more or less stiffness and 
lameness as a result of the skin injury. The injurious effects of the 
treatment were still well marked 8 days after the treatment. The 
cattle in this experiment were more seriously injured than others of 
the same herd sprayed with a 25 per cent emulsion of crude petro- 
leum, and were much more seriously injured than those in experiment 
No. 2 sprayed udth the arsenical solution before the addition of the 
crude petroleum. 

10407°— Bull. 144—12 3 



34 ARSENICAL DIPS FOR CATTLE TICKS. 

Cattle closely examined 7 and 8 days after spraying were free from 
ticks, and others seen 8 days after spraying during a ride through 
the herd were apparently free from ticks. 

Thirty-eight engorged ticks were removed from some of the cattle 
14 hours after spraying. Twenty-nine of these died without deposit- 
ing eggs. The remaining 9 laid a few eggs, none of which hatched. 
Thirty-four engorged ticks were removed fi'om the cattle 3 days 
after spraying. One of these laid a few eggs, none of which hatched ; 
the other 33 died without depositing eggs. Fourteen ticks collected 
October 22 from untreated cattle and kept under the same conditions 
as those from the sprayed cattle deposited numerous eggs, most of 
wliich hatched. Another lot of 6 engorged ticks taken from untreated 
cattle on the same date deposited about 1,000 eggs, about 100 of 
which hatched. None of 10 nymphs collected 14 hours after spraying 
molted, and 9 nymphs collected 3 days after spraying all failed to 
molt. All but 4 out of 25 nymphs collected October 22 from untreated 
cattle and kept under the same conditions as those from the sprayed 
cattle afterwards molted. 

ARSENIC AND ZINC SULPHATE DIP. 

Experiment No. 14- 

August 7, 1909, a tick-mfested calf was dipped at the Bureau 
Experiment Station in a dip consisting of arsenic trioxid, zinc sul- 
phate, and water, contaming 0.476 arsenic trioxid in solution. ^ 

In this dip the same ingredients were used and in the same pro- 
portion as those used in the so-called "arsenical dip of Trasbot" 
employed in France for dipping scabby sheep, omittmg, however, 
the aloes which is included in Trasbot's dip, with the further differ- 
ence also that only about half the arsenic used was brought into 
solution, although it was submitted to prolonged boiling. 

The calf had been artificially infested and at the time of dipping 
ticks in all stages of development were present. The period of 
immersion in the bath was two minutes, and after dipping the calf 
was kept in a noninfested pen. The calf was seriously injured by 
the dip. The skin in places became much thickened and cracked, 
with much exfoliation and some loss of hair, and the animal fell 
off in flesh considerably. Recovery from the effects of the dipping 
required nearly a month. No ticks matured later than two days 
after dipping and all that matured after dipping died without deposit- 
ing eggs. The calf was entirely free from live ticks six days after 
dipping. 

Immediately after dipping, August 7, 49 engorged ticks were 
removed from the calf. All of these died without depositing eggs. 

1 Analysis made in Biochemic Division. 



AESENIC AND ZINC SULPHATE DIP. 35 

For comparison it may be noted that 24 out of a lot of 25 small 
and only partially engorged ticks collected from an undipped animal 
on the same date and kept under the same conditions deposited 
eggs which weighed 0.3036 gram, 12 per cent of which afterwards 
hatched. 

August 8, 5 engorged and 7 partially engorged females were 
collected from the calf, all of which died without depositing eggs. 
For comparison note that 1 fully engorged and 3 partially engorged 
females collected from an undipped calf on August 8 and kept under 
the same conditions as the ticks from the dipped calf all deposited 
eggs weighing 0.1365 gram, 75 per cent of wliich hatched. . 

August 9, after which date no ticks matured on the calf, 6 nearly 
replete females were collected, all of which died without depositing 
eggs. For comparison note that 1 female, nearly replete, col- 
lected from an undipped calf on the same date and kept under 
the same conditions as the ticks from the dipped calf deposited 
eggs weighing 0.0295 gram, 80 per cent of which hatched. 

The dip used in this experiment had the effect of destroying 
not only the younger ticks but also affected the engorged and nearly 
engorged ticks so seriously that they died without depositing eggs. 

Judging from the results of this experiment, the dip used, although 
it proved very efficacious as a tick killer, has no practical value 
as a cattle dip on account of its severe effects and the difficulty of 
dissolving the arsenic in preparing it. 

Experiment No. 15. 

August 8, 1909, 46 fully engorged female ticfe were collected 
from an undipped calf at the Bureau Experiment Station. These 
were immersed for two minutes in some of the solution used in 
experiment No. 14, which contained 0.476 per cent arsenic trioxid. 
After dipping, the ticks were dried on filter paper, placed in a Petri 
dish, and kept under observation m the laboratory. Forty-four 
of these ticks died without depositing eggs. The other 2 deposited 
eggs amounting ui aggregate weight to 0.0078 gram, none of wliich 
hatched. Out of 46 engorged ticks collected August 8 and kept 
under the same conditions as the ticks referred to above, except 
that they were not dipped, 45 deposited eggs whose aggregate weight 
amounted to 2.5975 grams, and 98 per cent of them hatched. Another 
lot of 4 females collected August 8 and kept under the same condi- 
tions deposited eggs weighing 0.1365 gram 75 per cent of which 
hatched. 



36 ARSENICAL DIPS TOR CATTLE. TICKS. 

ARSENIC-ALUM DIP. 

Experiment No. 16. 

August 10, 1909, a calf which had been artificially infested with 
ticks was dipped at the Bureau Experiment Station in a dip con- 
sisting of arsenic trioxid, alum, and water, containing 0.495 per cent 
arsenic trioxid in solution.^ This dip is similar to a dip used more 
or less in Europe for the treatment of sheep scab. 

At the time of dipping, ticks in all stages of development were 
present on the calf, llie animal was immersed in the dip for two 
minutes. After dipping the calf was kept in a noninfested pen. 

The skin of the calf was slightly injured by the dipping to the 
extent that in places some thickening with exfoliation occurred, 
which was still noticeable August 20, but had disappeared by Septem- 
ber 9. The animal was entirely free from ticks within eight days after 
dipping. No ticks matured on the calf later than three days after 
dipping. All that matured either died without ovipositing or 
deposited only a few eggs, none of which hatched. 

This dip was very efficacious and produced only slight sldn injury. 
The difficulty of preparing it, however — that is, of dissolving the 
arsenic trioxid — renders it undesirable for practical use. 

August 10, immediately after dippmg, 43 engorged and nearly 
engorged female ticks were collected. All of these died without 
depositing eggs. Later m the same day 19 engorged females were 
collected, all but 4 of which died without depositing eggs. These 
4 deposited eggs amounting to 0.013 gram in weight, none of which 
hatched. For comparison with the above it may be noted that 
21 out of a lot of 22 females, none fully grown, coUected August 
10 from an undipped animal and kept under the same conditions 
as those from the dipped calf deposited eggs aggregating 0.4242 
gram in weight, and that 50 per cent of these hatched. 

August 11, 18 females (6 engorged and 12 partially engorged) 
were coUected, 3 of which deposited eggs weighing 0.0495 gram, 
none of which hatched. The other 15 died without depositing 
eggs. In comparison note that 18 females (4 fully engorged and 
14 nearly engorged) collected from undipped cattle August 11 
and kept under the same conditions all deposited eggs weighing 
0.2441 gram, 40 per cent of wliich hatched. 

August 12, two days after dippmg, 14 females (6 fully engorged 
and 8 nearly engorged) were collected, and 2 of these laid eggs 
weighing 0.0082 gram. The other 12 ticks died without ovipositing. 
None of the eggs hatched. In comparison note that 5 females (3 
fuUy engorged and 2 partially engorged) collected from undipped 

1 Analysis made in Biocliemic Division, 



AESENIC-ALUM AND SODIUM AESENATE DIPS. 37 

cattle August 12 and kept under the same conditions all deposited 
eggs weighing 0.1555 gram, and that 60 per cent of these hatched. 
August 13 was the last day on which any ticks matured on the 
calf in this experiment. On this date 6 females (3 fully engorged 
and 3 partially engorged) were removed, 1 of which survived 
to deposit eggs weighing 0.0293 gram. None of these hatched. 
In comparison note that 17 engorged females collected from an 
undipped calf August 13 and kept under the same conditions as 
those from the dipped calf all deposited eggs weighing 0.8953 gram, 
and that 97 per cent of these hatched. It may also be noted that 
1 engorged female removed from an undipped calf August 13, and 
kept under the same conditions as the ticks from the dipped calf, 
deposited eggs weighing 0.0426 gram, and that 40 per cent of these 
hatched. 

Experiment No. 17. 

Fifty-nine engorged female ticks, collected August 10, 1909, from 
cattle at the Bureau Experiment Station, were immersed two minutes 
on August 11 in some of the dip used in Experiment No. 16, which 
contained 0.495 per cent arsenic trloxid. After dipping, the ticks 
were dried on filter paper, placed in a Petri dish, and kept under 
observation in the laboratory. Fifty-seven of these ticks died with- 
out depositing eggs. The other two deposited eggs whose aggregate 
weight amounted to 0.0123 gram. None of these eggs hatched. 

Fifty-eight in a lot of 59 undipped ticks, collected at the same time 
as those just referred to, deposited eggs whose aggregate weight 
equaled 2.773 grams, and 97 per cent of which hatched, ha\dng been 
kept under the same conditions as those from the dipped ticks. 

SODIUM ARSENATE DIP. 

Experiment No. IS. 

November 10, 1910, 60 engorged ticks collected from an infested 
bull at the Bureau Experiment Station were divided into 3 lots of 
20 each and kept in the laboratory in Petri dishes, all under similar 
conditions. Sufficient moisture to insure the hatching of normal 
eggs was provided by the presence of sand in the dishes, which was 
kept moist. 

Lot No. 1 was dipped two minutes on November 10 in a neutral 
solution of sodium arsenate containing an equivalent of 0.22 per cent 
arsenic trioxid.^ 

Lot No. 2 was dipped two minutes on the same date in a sHghtly 
alkaline solution of sodium arsenate containing an equivalent of 0.22 
per cent arsenic trioxid.* 

1 Solution prepared in Biochemic Division. 



38 ARSENICAL DIPS FOR CATTLE TICKS. 

Lot No. 3 was not dipped. 

All but one of the first lot of ticks deposited eggs, of which 1 per 
cent hatched. All of the second lot deposited eggs, of which 2 per 
cent hatched. The third lot of ticks, wliich were not dipped, all 
deposited eggs, of which 99 per cent hatched. 

SODIUM SULPHARSENITE DIP. 

Experiment No. 19. 

Twenty-two engorged ticks, collected October 19 and 20, 1910, from 
an infested bull at the Bureau Experiment Station, were dipped two 
minutes, October 21, in a shghtly alkahne solution of sodium sulph- 
arsenite containing an equivalent of 0.22 per cent arsenic trioxid.^ 
After dipping, these ticks were placed in a Petri dish and kept under 
observation in the laboratory. 

On the same date 22 engorged ticks collected at the same time and 
from the same animal as the preceding lot were dipped two minutes 
in an arsenic, soda, and ptae-tar dip, made October 20, which contained 
an equivalent of 0.22 per cent arsenic trioxid. 

A third lot of 22 engorged ticks also collected at the same time and 
from the same animal as the other two lots was kept under obser- 
vation undipped. Except as to dipping, all three lots were handled 
in the same manner and kept under the same conditions. 

Of the lot dipped in sodium sulpharsenite all but three deposited 
eggs. November 11 about half the eggs were normal, but none 
hatched. All of the ticks dipped in the arsenic, soda, and pine- tar dip 
cUed without ovipositing. All of the undipped ticks deposited eggs, 
practically all of which were normal on November 11. Less than 1 
per cent of the eggs hatched. 

The low relative humidity of the air of the laboratoiy was unfavor- 
able to the hatcliing of the eggs in this experiment. 

POTASSIUM ARSENITE DIP CONTAINING SOAP. 

Experiment No. 20. 

Twenty cattie heavily infested with ticks — some very heavily — 
were selected from a herd on the Kincon ranch, near Gregory, Tex., 
and these animals were dipped June 25, 1910. The dip used was a 
proprietary arsenical mixture. When dUuted the dip contained an 
equivalent of 0.202 per cent arsenic trioxid ^ in the form of potassium 
arsenite. It also contained some soap in addition to other ingredients 
of minor importance. The vat used was about 93 feet in length at 
the surface of the dip. Each animal was in the bath from 30 to 
60 seconds. After dipping, some of the cattle were kept in disin- 

1 Solution prepared in Biochemic Division. 2 Analysis made in Biochemic Division. 



POTASSIUM ARSENITE DIP CONTAINING SOAP. 39 

fected pens and some on infested pasture. Five to nine days after 
dipping an exfoliation of the epidermis appeared, rather marked in 
the case of 2 bulls, but generally slight in the case of the remaining 
animals, only 2 of which exliibited evidences of more than very mild 
skin injury. One of these showed a rather severe exfoUation on the 
escutcheon, thighs, dewlap, and other parts of the body, and the 
other showed a rather severe exfoUation of the skui on the dewlap, 
the exfohation on the posterior parts of the body being shght. The 
exfoUation in the case of the 2 buUs which were dipped but once was 
described as rather severe, causing a loss of hair on the inner side of 
the thighs. In no instance, however, was the exfoUation preceded by 
noticeable inflammation. 

July 5, 10 days after the first dipping, aU but 3 of the cattle were 
dipped a second time in the same vat and in the same dip, to which 
more water had been added. At the second cUpping the cUp con- 
tained an equivalent of 0.197 per cent arsenic trioxid.^ Following 
the second dipping the cattle which had been on infested pasture 
between dippings were returned to the infested pasture, except 2 
which were placed in a disinfected pen. Those which had been in 
disinfected pens between dippings were returned to the same pens. 

The cattle were examined incU^ddually on June' 25, before dipping, 
and every few days thereafter, the final examination being made on 
July 18, two weeks after the second dipping. 

Eight to 13 days after the second dipping a fresh exfoUation of the 
epidermis became evident on some of the animals, but it was, as a 
rule, much less marked than the exfoUation following the first dipping. 

Within four days after the first dipping most of the ticks were dead. 
All but 7 of the cattle, so far as could be determined from careful 
examination, were free from live ticks 9 days after the first dipping. 
At that time the ticks found aUve were 2 recently molted females, 
8 males (6 of them newly molted), and 6 nymphs. The following day 
an additional male was found, making 17 the total recorded number 
of Uve ticks present on the cattle just prior to the second dipping. 

None of the 3 cattle which were dipped but once and subsequently 
kept in a disinfected pen showed any infestation after July 2, 7 
days after dipping. A very plump female one-fourth of an inch long 
was found on one of the twice-dipped cattle 2 days after the second 
dipping. This tick was found dead 2 days later. Four days after 
the second dipping a very plump female one-third of an inch long 
was found on another animal. This tick was removed and placed 
in a pill box. It died without depositing eggs. At the final examina- 
tion a female tick which had molted several days before was found. 
Except for larvae which were found at the final examination on the 
cattle which occupied infested pasture, these 3 ticks were all that 

1 Analysis made in Biochemic Division. 



40 ARSENICAL DIPS FOR CATTLE TICKS. 

were found upon the cattle subsequent to the second dippmg. Most 
of the larvae found at the final examination were not more than 1 to 
2 days old (reckoning from date of attachment). Only one was found 
which was older. This one had possibly been attached for as long 
as 4 days. 

From time to tune after the first dipping ticks were removed from 
the dipped cattle and placed in boxes for further observation, and at 
the same time ticks were removed from undipped cattle and kept under 
the same conditions for comparison with those from the dipped cattle. 

All of the engorged females (10) removed from the cattle imme- 
diately after dippmg died without depositing eggs. Four out of 20 
partly engorged females deposited eggs, none of which hatched. 
Eleven engorged and 25 partly engorged females removed from 
undipped cattle on the same date deposited eggs, about 50 per cent 
of which hatched. 

Two days after dipping, 48 engorged and 26 partially engorged 
females were removed from the dipped cattle. About 20 of the 
former and 5 of the latter deposited eggs. None of tlie eggs laid by 
the latter hatched and about 1 per cent of those laid by the former 
hatched. On the same date 14 female ticks not more than half grown 
were removed from undipped cattle. About 3 per cent of the eggs 
deposited by these ticks hatched. 

Three days after dipping, 22 fully engorged and 18 partially engorged 
ticks were removed from the dipped cattle. About 10 of the former 
oviposited. Some of the latter also deposited eggs, none of which 
hatched. Less than 1 per cent of the eggs deposited by the engorged 
females hatched. On the same date 1 engorged and 13 partially 
engorged females were removed from undipped cattle. Most of these 
deposited eggs, and about 10 per cent of the eggs hatched. 

Four days after dipping, 3 partially engorged females were 
removed from the dipped cattle. All of these died without deposit- 
ing eggs. On the same date 3 females one-fourth to one-half 
grown were removed from undipped cattle. These deposited eggs, 60 
per cent of which hatched. 

Five days after dipping, 1 engorged female was removed from one 
of the dipped cattle. This tick died without ovipositmg. On the 
same date 1 engorged and 2 two-thu-ds grown females were removed 
from an undipped bull. All of these deposited eggs, 95 per cent 
of which hatched. 

Six days after dipping, a female tick not more than one-half grown 
was removed from one of the dipped cattle. This tick died without 
depositing eggs. 

Fourteen days after the first dipping and 4 days after the second 
dipping, a very plump female one-third of an inch long was 



POTASSIUM ARSENITE DIP CONTAINING SOAP. 41 

removed from one of the dipped cattle. This tick died without 
depositmg eggs. 

Immediately after dipping, 12 nymphs were removed from the 
dipped cattle. None of these molted. At the same time 20 nymphs 
were removed from undipped cattle. All but one of these molted. 

Two days after dipping, 17 nymphs were removed from the dipped 
cattle. None of these molted. On the same date 2 nymphs were 
removed from undipped cattle, and both molted. 

Three days after dipping, 41 nymphs were removed from the dipped 
cattle. None of these molted. 

Four days after dipping, 54 nymphs were removed from the dipped 
cattle. None of these molted. On the same date 42 nymphs were 
removed from undipped cattle, 27 of which molted. 

Five days after dippmg, 46 nymphs were removed from the dipped 
cattle. None of these molted. On the same date 12 nymphs were 
removed from an undipped bull, and 10 of them molted. 

Six days after dipping, 1 nymph was removed from one of the 
dipped cattle. This nymph failed to molt. 

Experiment No. 21. 

This experiment was conducted under the supervision of Dr. Dick 
E. Warner, veterinary inspector, assisted by Mr. Charles H. Gibson, 
agent in tick eradication, both of the Bureau of Animal Industry. 
The following account is summarized from Dr. Warner's report: 

October 26, 1910, 20 head of tick-infested cattle were dipped on 
the Woodley ranch near Tulsa, Olda. These cattle were all grossly 
infested with ticks in all stages of development, including some larvae. 
The infestation was most pronounced along the inside of the thighs, 
on the escutcheon, neck, dewlap, and along the anterior border of 
the scapula. The animals were infested to a less degree on all other 
parts of the body. In several instances the infestation reached the 
degree known as ''shingled,^' and in some instances ticks were noted 
within the ears. All the cattle carried a heavy winter coat of hair. 
All were m good health at the time of dipping with the exception of 2, 
which presented the appearance of having recently suffered from an 
attack of fever. During the experiment these 2 animals constantly 
improved m condition. 

The dip used was a proprietary arsenical dip of the same brand as 
that used in experiment No. 20. When diluted for use it contained 
an equivalent of 0.224 per cent arsenic trioxid.^ 

The vat m which the cattle were dipped was 31 feet in length at the 
surface of the dip. Each animal was held in the bath from 13 to 15 
seconds. After dipping, 4 of the cattle were placed in a tick-free pen, 
and the remaining 16 in a small infested pasture. In view of the cool 

1 Analysis made in Blochemlc Division. 



42 ARSENICAL DIPS FOR CATTLE TICKS. 

weather prevailing, it is probable that the latter were exposed to but 
slight chances of reinfestation. A heavy frost occurred every night 
but one during the experiment, and at times ice formed during the 
night to a thickness of one-third of an inch. There was no rain during 
the experiment. 

After dipping, the cattle were examined at intervals of a few days. 
A slight exfoliation of the epidermis was noted, beginning 4 days 
after dipping. At no time did this exfoliation become extensive, nor 
was it accompanied by inflammation. No injury to the skin or 
hair was noted. 

Most of the ticks had disappeared by the fourth day after dipping. 
No live larval ticks were found subsequent to dipping. Eight days 
after dipping 2 live males were found on 1 animal. On 8 cattle 
14 nymphs apparently alive were found 8 days after dippmg. On 
18 of the cattle 99 live females, from newly molted to one-half 
grown, were found 8 dhjs after dipping. Thirty-one female ticks 
over half grown were found on 6 of the cattle 8 days after dippmg. 
Thirteen of these were stated to be mature. Two cattle were free 
from ticks 8 days after dippmg. One of these had been kept in 
the disinfected pen, the other in the infested pasture. 

November 4, 18 of the cattle were dipped again. The other 2 
were not dipped a second tune, but were kept under observation for 
23 days after dipping and were still infested with ticks at the end of 
this time. Both of these animals occupied the infested pasture after 
dipping. No live nymphs were noted on one of these cattle subse- 
quent to October 30. One nymph apparently aUve was noted on 
the other 8 days after dipping, but none was found subsequently. 
Twenty-three days after dipping the only ticks found on the cattle 
which were dipped but once were 3 females on one and 1 female on 
the other. 

At the second cUpping the dip which was left in the vat since the 
first dipping was used. A sample taken at the time of the second 
dipping showed the presence of an equivalent of 0.233 per cent 
arsenic trioxid.^ Each animal dipped was held in the bath 13 to 15 
seconds, except one, wliich was held but 9 seconds. Following the 
second dipping 12 of the cattle dipped were placed in the infested 
pasture and 6 in the disinfected pen. Four of these 6 had occupied 
the pen between the 2 dippings; the other 2 had been in the infested 
pasture. 

The effects of the second dipping on the skin were described as 
extremely mild, consisting of slight exfoliation, noted in the case of 
only 2 animals. Twelve days after the second dipping the exfolia- 
tion due to the first dipping contiaued in a mild form, unaccompa- 

1 Analysis made in Biochemic Division. 



POTASSIUM ARSENITE DIP CONTAINING SOAP. 43 

nied by inflammation, and without noticeable injuiy to the hair or 
skin. 

A nymph apparently alive was found on each of 2 cattle out of a 
total of 7 examined two days after the second dipping. No live 
nymphs were afterwards found on any of the twice-dipped cattle. 
No live males were found subsequent to the second cUpping. On 5 
of the 7 cattle examined, 14 female ticks were found, ranging in 
development from newly molted to two-thirds grown. The other 2 
cattle were free from ticks and none was afterwards found on them. 
Four days after the second dipping 11 cattle were examined and 2 
found to be infested. Two female ticks one-sixth grown and 1 
female tick two-tliirds grown were found on 1 of the 2 infested 
cattle, and 1 female tick about one-half grown on the other, a total 
of 4 ticks. The other 9 cattle were free from ticks and none was 
found on them subsequently. Six days after the second dipping 8 
cattle were examined and 1 of them was found to be infested with a 
female tick one-half grown. Tliis animal was 1 of the 2 found in- 
fested 4 days after the second dipping. Eight days after the second 
chpping 10 cattle were examined, including the 1 found infested 6 
days after dipping. No live ticks were found. Ten days after the 
second dipping 8 cattle were examined and on 1 of them was found 
a female tick over one-half grown. This was the last tick found 
subsequent to the second dipping. The animal on which it was 
found was 1 of those examined 6 days after dipping and at that 
time was apparently free from ticks. The tick showed evidences of 
the injurious effects of the dip. Two days later or 12 days after the 
second dipping this tick had disappeared. Fourteen days after the 
second dipping all of the twice-dipped cattle were free from ticks. 

From time to time after the first dipping ticks were removed from 
the dipped cattle and placed in boxes for further observation. Ticks 
were also removed from undipped cattle and kept under similar con- 
cUtions for comparison with those from the dipped cattle. 

Engorged and 'partially engorged females. — One hour after the first 
dipping 100 engorged females were removed from the dipped cattle. 
AH of these died without depositing eggs. Another lot of 100 en- 
gorged females removed at the same time from undipped cattle all 
deposited eggs. 

Two days after dipping 60 engorged or nearly engorged female 
ticks and 10 half-growa females were removed. The latter died 
without ovipositing. Of the former, 48 deposited eggs m number 
less than normal. At the same time 40 engorged or nearly engorged 
females and 30 half-grown females were removed from undipped 
cattle. All of the former and 3 of the latter deposited eggs. 

Four days after dipping 15 engorged females and 12 one-third to 
one-half grown females were removed from the dipped cattle. None 



44 ARSENICAL DIPS TOR CATTLE TICKS. 

of the latter deposited eggs. Six of the former deposited eggs in 
number less than normal. On the same date 15 engorged females 
and 12 one- third to one-half gro-wn females were removed from 
undipped cattle. All of the former and none of the latter deposited 

eggs. _ . 

Six days after dipping 12 engorged females and 7 one- third to one- 
half grown females were removed from the dipped cattle. Three of 
the former deposited eggs in number less than normal and none of 
the latter deposited eggs. On the same date 12 engorged or nearly- 
engorged females and 7 one-tliird to one-half grown females were 
removed from undipped cattle. All of the former and none of the 
latter deposited eggs. 

The ticks wliich had been removed from the cattle and eggs which 
they had deposited were sent to the laboratoiy of the Zoological 
Division at Washington in the early part of December. They were 
in such poor condition when received that it was considered useless 
to make any further observations upon them. 

Nym-iJihs. — Two days after dipping 15 nymphs were removed from 
the dipped cattle. All of these died without molting. On the same 
date 20 nymphs were removed from undipped cattle. Two of these 
molted, the others died without molting. 

Four days after dipping 15 nymphs were removed from the dipped 
cattle. Two of these molted, the others died without molting. On 
the same date 15 nymphs were removed from undipped cattle. 
Three of these molted, the others died without molting. 

Six days after dipping 4 nymphs were removed from the dipped 
cattle. All died without molting. On the same date 4 nymphs 
were removed from undipped cattle. All died without molting. 

EFFECT OF REPEATED APPLICATIONS OF THE ARSENIC, SODA, AND 

PINE-TAR DIP. 

Experiment No. 22. 

Tliis experiment, though not concerned with the efficacy of 
arsenical dips, may be recorded here inasmuch as it has a bearing 
upon the question of the injurious effects of these clips upon cattle. 

Beginning June 23, 1910, 2 lots of calves of 3 head each were 
dipped repeatedly at intervals until near the end of October. , A 
tliird lot of 3 was kept under observation undipped. All 3 lots were 
kept together in the same yard and stable at the Bureau Experiment 
Station under the same conditions except as to dipping. 

Lots A and B were cUpped June 23 in a dip made from 7 pounds of 
arsenic trioxid, 6^ pounds of sodium carbonate (anhydrous), 0.7 
gallon of pine tar, and sufficient water to make a total of 350 gallons. 



EFFECT OF EEPEATED APPLICATIONS. 45 

This dip contaiaed sodium arsenite equivalent in amount to 0.217 
per cent arsenic trioxid.^ 

One week later lot A was dipped again in the same dip and there- 
after was dipped every two weeks until October 20, when the last 
dipping was made. At the last dipping a freshly prepared dip was 
used, wliich was mixed in the same proportions as the dip made in 
June, and contained sodium arsenite in solution equivalent to 0.22 
per cent arsenic trioxid.^ 

Lot B was dipped every three weeks after the first dipping, using 
the dip made June 23. The last dipping was made on October 27. 
At this dipping the freshly prepared dip made October 20 was used. 

The cattle of lot A were accordingly dipped 10 times and those of 
lot B 7 times. Each animal when dipped was kept in the bath 2 
minutes. Once a week the cattle were weighed and examined. 

One week after the first dippmg 5 of the 6 animals dipped showed 
a slight scurfy condition of the skin on different parts of the body, 
but no irritation. The hair was rather dry and rough. 

Two weeks after the first dipping and one week after the second 
dipping, one of the cattle in lot A showed a moderate dandruff-like 
exfoliation on the neck, inner side of thighs, and the flank. Another 
showed some rouglmess of the skin on the inner side of the thighs 
and the third showed a very slight roughness of the sldn in the same 
location. One of the cattle in lot B, two weeks after dipping^ 
showed considerable epidermal exfoliation of a dandruff-like character 
on the brisket and inner side of thighs. Another showed a very slight 
roughness on the inner side of one thigh, and the third a rough exfolia- 
tion on the inner side of both thighs. 

Three weeks after the first dipping and two weeks after the second 
dipping, one of the cattle in lot A had a slight scurf in the hair on the 
brisket and on the elbows. Another showed a slight roughness of the 
skin on the inner side of the thighs. The skin of the third calf was 
normal. On the same day one of the animals of the other lot which 
had been dipped 3 weeks before was scurfy on the brisket, and 
the skin on the inner side of the thighs was slightly rough. Another 
had a slight loose scurf on the inner side of the thighs, and the third 
showed some scurf and scale on the inner side of thighs, peeling off 
with slight loss of hair. 

By August 4 all evidences of any injurious action of the dip on the 
skin of the dipped animals had disappeared, and no signs of any 
action of the dip on the skm were thereafter observed except that at 
times the hair of the dipped animals appeared to be somewhat dryer 
than that of the undipped animals. The freshly prepared dip used 

1 Analysis made in Biochemic Division of a sample taken June 23. 

2 Analysis made in Biochemic Division. 



46 AUSENICAL DIPS FOB CATTLE TICKS. 

at the final dipping had no noticeable effect upon the skin. During 
the progress of the experiment the cattle of all three lots became 
more or less affected with ringworm, upon which the dip had no 
apparent effect. 

July 29, one of the cattle in lot C, the undipped lot, died. The 
lungs were pneumonic with many lung worms present. 

August 13, one of the animals in lot B died after symptoms of 
pneumonia. On post-mortem the lungs were found to be in a pneu- 
monic condition, and the trachea was occluded with a mass of lung 
worms. 

Other calves in the three lots of cattle presented symptoms from 
time to time suggesting the presence of lung worms, but the two just 
referred to were the only ones which died. Another calf was added 
to lot C to take the place of the one which died, but lot B was 
continued after August 13 with only two calves. 

The three calves in lot A on June 23 weighed 172.5 pounds, 210 
pounds, and 235 pounds, respectively, and on November 3, at the 
close of the experiment, 240, 260, and 315 pounds, respectively. The 
two calves in lot B which survived weighed, respectively, 215 and 
242.5 pounds at the beginning of the experiment and 285 and 365 
pounds at the end of the experiment. 

The two surviving calves of the three original animals in lot C, the 
undipped lot, weighed, respectively, 232.5 and 342.5 pounds at the 
beginning of the experiment and 415 and 570 pounds at the end of the 
experiment. The calf substituted for the one that died weighed 180 
pounds August 4 and 240 pounds at the close of the experiment. At 
times the animals in all three lots fell back in weight, but on the whole 
they showed a gradual increase from firsji to last. 

From the foregoing figures it is seen that the average gain in weight 
of the cattle in lot A was 32 per cent, in lot B 42 per cent, and in the 
undipped lot C, assuming that the substitute calf gained 30 pounds 
from June 23 till August 4, when it entered the experiment, 68 per 
cent. Apparently the gain in weight was diminished as a result of 
dipping, but the number of cattle in the experiment was too small for 
any definite conclusion to be drawn in regard to this point. The fact 
also that some of the cattle were suffering more or less from lung- 
worm infection is a factor which would affect the validity of any gen- 
eral conclusion that might be drawn from this experiment as to the 
relative gam in weight shown by cattle repeatedly dipped in arsenical 
dip, as compared with undipped cattle. 

In view of the oxidation of the dip used in the present experiment 
which began to occur at some time subsequent to the third dipping of 
lot A and the second dipping of lot B, the value of the experiment 
is less than it would have been had freslily made dips been prepared 
from time to time. The effects of repeated applications of freshly 



EFFECTS OF ARSENICAL DIPS ON CATTLE. 47 

made dips might, of course, have proved more serious than those 
which occurred as a result of the repeated use of the oxidized dip. 
The experiment was therefore unsatisfactory so far as concerns the 
question as to the amount of mjury to cattle which may be expected 
when they are dipped repeatedly at intervals of two to three weeks 
during a period of several months in an arsenic, soda, and pine-tar dip 
containing sodium arsenite equivalent to 0.22 per cent arsenic trioxid. 

DISCUSSION OF RESULTS. 
EFFECTS OF ARSENICAL DIPS ON CATTLE. 

The effects of the dips upon the cattle in the various experiments 
were almost invariably slight. 

No constitutional symptoms were observed except in one experi- 
ment (No. 14), in which a dip containing 0.476 per cent of arsenic tri- 
oxid was used, and these may have been secondary to severe skin 
lesions. The calf clipped in this strong solution lost considerably in 
weight and did not begin to recover from the effects of the dip until 
about a month after dipping. In another experiment (No. 16) a calf 
dipped in a stUl stronger solution (0.495 per cent) of arsenic trioxid 
showed no signs of injury other than slight skin injury. Cattle not 
infested with ticks, dipped repeatedly in a dip containing an equiva- 
lent of about 0.22 per cent arsenic trioxid at intervals of two and 
three weeks gained less in weight than other uninfested cattle kept 
under the same conditions undipped, but it is uncertain whether this 
difference was due to the dipping. (See experunent No. 22.) 

In all cases in which cattle were dipped or sprayed once or twice in 
arsenical dips containing an equivalent of from 0.16 to 0.24 per cent 
arsenic trioxid the injurious effects observed were confined to the 
action of the dips upon the skin, and scarcely ever was this action 
more than very mild, though in some cases the animals were treated 
in hot weather when the injurious effects from dipping are especially 
likely to appear. The signs of the effects of dipping on the skin in 
various instances became evident in from 3 to 9 days after the treat- 
ment, at which time a more or less well-marked epidermal exfoliation 
or dandruff-like peeling of the superficial layers of the skin appeared, 
confined as a rule to the dewlap, neck, escutcheon, inner side of 
thighs, and scrotum. No marked inflammation preceded the exfolia- 
tion, though occasionally a slight irritation of the skin in places was 
observed. 

In a number of cases the skin became somewhat thickened on cer- 
tain parts of the body, namely on the escutcheon, inner side of the 
thighs, dewlap, and neck. Rarely was cracking of the thickened skin 
observed. In one experiment (No. 13) in which cattle were sprayed 
once with an arsenical solution containing an equivalent of about 0.17 



48 AESENICAL DIPS FOR CATTLE TICKS. 

per cent arsenic trioxid to which had been added 10 per cent crude 
petroleum emulsified with soap, rather severe skin injury was observed 
in the case of some of the animals, consisting in exfoliation, thicken- 
ing, and cracking of the skin, with evident soreness, which caused the 
animals to become stiff and lame. These effects were apparently 
largely due to the oil, as the skin of cattle sprayed m the same dip 
before the addition of the crude petroleum showed scarcely any signs 
of injury (experiment No. 2). In the case of a few animals in some 
of the experiments a slight loss of hair accompanied the exfoliation. 
BuUs seemed to be more liable to skin injury than cows and steers. 
The effects of a second dipping so far as observed were always less 
than those of the first. When fresh exfoliation occurred as a result 
of a second dipping given within two weeks after the first, it first 
became noticeable in from 8 to 13 days after the second dipping. 

In tliis connection it should be noted that it is a matter of common 
observation and shown very clearly in many of the experiments 
detailed in tliis paper, that there is a great difference in the suscepti- 
bihty of individual animals to the effects of dips apphed in the same 
way and under similar conditions. The skin affections produced by 
a dip appear also to depend on the method employed in applying it. 
Watkins-Pitchford ^ has found that an arsenical dip wliich is satis- 
factory from the standpoint of its effects on the skin when used as 
a spray, is entirely too strong when used as a dip. 

In our experiments, cattle dipped ten times with an interval of one 
week between the first two dippings and with an interval of two 
weeks between the second and tliird and succeeding dippings and 
cattle dipped seven times at intervals of three weeks showed scarcely 
any evidences of the effects of the dip upon the skin (experiment 
No. 22). The dip used in tliis experiment originally contained 
sodium arsenite equivalent to 0.217 per cent arsenic trioxid, but at 
some tune between three weeks and three months after the first dip- 
ping the sodium arsenite had become largelj^ oxidized to sodium 
arsenate. It is probable that sodium arsenate is less active on the 
skin than sodium arsenite, hence it is possible that if a freshly made 
arsenical dip had been used at each dipping, the repeated apphcations 
might have had more effect upon the cattle, though it should be 
noted that at the tenth dipping of one lot of cattle, and the seventh 
dipping of the other lot, a freshly prepared dip containing an equiva- 
lent of 0,22 per cent arsenic trioxid was used without producing any 
noticeable skin injury. 

In one experiment (No. 12, lot C) in wliich a dip, containing an equiv- 
alent of 0.222 per cent arsenic trioxid with some soap, was used, the 
effects on the skin, though not serious, were somewhat more marked 

1 Natal Agricultural Journal, Pietermaritzburg, vol. 12 (4), 1909, pp. 430-459; vol. 15 (5), 1910, pp. 577-602. 



EFFECTS OF ARSENICAL DIPS ON TICKS. 49 

than those usually observed following the use of a simple arsenic, soda, 
and pine-tar dip, containing the same percentage of arsenic. The 
effects of a proprietary dip, wliich contained soap and other ingre- 
dients of minor importance in addition to arsenic, as observed in 
two experiments (Nos. 20 and 21), were apparently somewhat greater 
than those resulting from the above-mentioned dip containing soap 
or the ordinary arsenic, soda, and pine-tar dip. 

The following conclusions may be drawn from the various experi- 
ments as to the effects of arsenical dips upon cattle: 

Cattle may be safely dipped or sprayed with an arsenical dip con- 
taining an equivalent of 0.24 per cent arsenic trioxid or less, and the 
treatment once repeated seven or more days later,^ the only injury 
to be expected as a rule being more or less epidermal exfoliation, 
and sometimes sHght soreness or tenderness of the skin, local in 
character. 

It is understood in stating the foregoing conclusions that accidents 
resulting from a lack of proper precautions to avoid the drinking of 
the dip by cattle are excluded from consideration, and it should also 
be noted that cattle are liable to suffer severely after cUpping, especi- 
ally in hot weather, if driven long distances, or even if allowed to run 
short distances so that they become overheated. This latter fact is 
stated on the basis of observations made by various persons who 
have had considerable practical experience in the use of arsenical dips. 
On the whole, however, in view of the hundreds of thousands of cattle 
on farms and ranches which have been treated with arsenical dips 
under all sorts of conditions, the number of cases of injury reported has 
been remarkably small. 

In tliis connection it is of interest to note that Watkins-Pitchford ^ 
in observations made in South Africa, finds that dipping work oxen 
every fifth day in an arsenical dip called the ''Laboratory Dip" (con- 
taining as its essential ingredients 8^ pounds of arsenite of soda, 80 
per cent arsenic, to 400 gallons (imperial)^ of water) does not interfere 
in any way with cattle being worked regularly. 

EFFECTS OF ARSENICAL DIPS ON TICKS. 

The experiments discussed in the present paper have fully con- 
firmed the observations of various investigators and practical users 
of arsenical dips who have found that ticks are very sensitive to 
arsenic. Little is known, however, as to the avenue by wliich arsenic 
enters the body of ticks when arsenical dips are used. 

1 If many treatments are given the Intervals between treatments should not be less than two weeks. 

" Loo. cit. 

8 One imperial gallon equals approximately 1.2 U. S. gallons. 

10407°— Bull. 144—12 4 



50 ARSENICAL DIPS FOR CATTLE TICKS. 

W. F. Cooper^ states that he has proved "that on the application 
of an arsenical solution to the skin of a beast, the arsenic penetrated 
the skin and was to be found in all the tissues of the beast, and 
further, that this took place very rapidly." In his experiments a 
considerable amount of arsenic was found in blood taken from the 
heart as early as eighteen hours after dipping. Contrary to the 
results obtained by Mr. Cooper, a committee appointed by the board 
of health, Natal, South Africa (Agricultural Journal of the Cape of 
Good Hope, vol. 37, No. 6, December, 1910, p. 699), has found that no 
trace of arsenic was present in the muscles, liver, kidneys, or stomach 
of cattle dipped repeatedly at short intervals in arsenical solutions. 
With regard to the presence of arsenic on the coat and in the skin of 
animals treated regularly with an arsenical dip, Watldns-Pitchford ^ 
has furnished some interesting observations. He appears to have 
shown by analysis of samples of skin a foot square from animals that 
have been dipped or sprayed regularly, that there is an accumulation 
of arsenic in the skin up to a certain maximum amount wliich is 
rather constant and can not be materially raised by shortening the 
interval between treatments. He believes that there is not merely 
a mechanical deposition of arsenic in the skin, but that the amount 
is controlled by vital processes, any excess of arsenic beyond a certain 
amount being rapidly taken up by the blood and ehminated in the 
urine. The amount of arsenic in the hair and scurf is raised by spray- 
ing the skin immediately after death, while that in the sldn, according 
to the statement of the author, is not, but the evidence presented on 
this last point is not complete. It was also found that the amount 
of arsenic in the hair and scurf of a square foot of skin was always 
greater than that in the skin itself. 

The same author has shown by experiments, which, however, are 
rather limited, that animals that have been treated with an arsenical 
dip are poisonous to ticks ; that this toxicity increases with the number 
of treatments, and that in regularly treated animals, it is less, in 
accordance with the length of the period elapsing after the last treat- 
ment. It was also found that when infested animals regularly treated 
and others not thus treated were dipped, the ticks on the former per- 
ished much more quickly than on the latter. 

That ticks are not killed by arsenic present in the blood, the author 
claims to have shown by spraying an animal all over, except on a 
certain area where ticks had been placed, when the ticks remained 
unaffected. On the other hand, the poisonous effects do not appear 
to be due to a simple deposition of arsenic on the skin, because when 
ticks are permitted to attach to an area of skin, in a regularly treated 
anuual, wliich has been previously shaved and washed to remove any 

1 Journal of Agricultural Science, vol. 3, part 3, p. 288, Cambridge, 1910. 

- Natal Agricultural Journal, vol. 15 (3), pp. 312-329, Pietermaritzburg, 1910. 



EFFECTS OF ARSENICAL DIPS ON TICKS. 51 

arsenic on the surface, they nevertheless succumb. Some interestmg 
observations were also made with regard to the persistence of arsenic 
in the hair. In one instance arsenic was found in the hair 6 months 
and in another 7 months after treatment. A case is referred to in 
which 3 inches of rainfall did not lower appreciably the amount of 
arsenic in the coat. 

Although Watkins-Pitchford's observations indicate that arsenic 
accumulates in the skin of cattle when they are dipped repeatedly, 
it is certain that the action of arsenical dips is not entirely dependent 
upon the arsenic which ticks may obtain from the skin for the reason 
that ticks removed from cattle immediately after dipping may after- 
wards exhibit evidences of having been acted upon by the dip. Our 
slight knowledge of the mechanism of the action of arsenic upon ticks, 
therefore, allows only the general statement that when arsenical dips 
are used the poison enters the bodies of the ticks in one or more of 
the following four ways, namely, (1) through the mouth; (2) through 
the breathing pores; (3) through other openings of the body; or (4) by 
absorption through the cuticle. As a corollary to this statement it 
may be added that the poisonous action of these dips upon ticks is 
certainly not entirely dependent upon the arsenic which may be 
ingested indirectly from the skin of cattle after treatment, but is 
largely, if not chiefly, dependent upon that absorbed or ingested 
directly as a result of immersion in the dipping fluid. 

FEMALE TICKS. 

It was noted in the various experiments that, as a rule, after cattle 
had been treated with ai*senical dips the number of female ticks 
maturing became rapidly less day by day, and that it was exceptional 
to find any engorged ticks present a few days after the treatment. 
It is therefore evident that after treatment with an arsenical dip the 
vast majority of the young adult females die before they reach the 
engorged stage, and that the younger they are the less likely are they 
to survive and become engorged. 

In six experiments the cattle were found to be free from engorged 
ticks three to five days after the first treatment, in four other experi- 
ments they were free seven to nine days after treatment, in another 
they were nearly free five days after treatment, in another experi- 
ment all that were examined were free from engorged ticks eight 
days after treatment, and in two other experiments the cattle were 
nearly free from engorged ticks eight days after treatment. An idea 
of the marked effect of treatment upon female ticlvs may be obtained 
from the observations made in one experiment (No. 5) in which a 
record was kept of the number of ticks which reached the engorged 
stage on 2 calves after dipping in an arsenical dip containing an equiv- 
alent of 0.16 per cent arsenic trioxid. This dip contained consider- 
ably less arsenic than the dips usually employed. A third calf was 
kept under observation undipped, and the number of ticks maturing 



52 ARSENICAL DIPS TOE CATTLE. TICKS. 

on this animal from day to clay was recorded, as in the case of the 
2 dipped calves. On one of the dipped calves 1,340 ticks and on the 
other 1,907 ticks reached engorgement during the first week after 
dippmg. From the undipped calf 968 engorged ticks of which a re- 
cord was kept were collected during the same period. Subsequent 
to the first seven days after dipping only 67 and 37 ticks, respectively, 
reached engorgement on the dipped animals, whereas more than a 
thousand reached full maturity on the untreated calf. 

A question of great importance is that of the fate of the ticks which 
reach engorgement and fall from cattle subsequent to treatment with 
arsenical dips. In order to obtain data bearing upon this question 
engorged ticks were collected from the cattle m the various experi- 
ments immediately after treatment and on successive days thereafter, 
and kept under observation. Observations were likewise made upon 
ticks removed on corresponding dates from untreated cattle. These 
ticks were kept under the same conditions as those from the treated 
cattle, and thus served as "controls" or "checks" upon the latter. 
Excluding from consideration one experiment (No. 5 referred to in 
the precedmg paragraph) in wliich an unusually weak arsenical dip 
was used, about 70 lots of ticks varying in number from 1 to 100 each 
were removed from treated cattle in the various experiments. A 
somewhat smaller number of lots of ticks from untreated cattle were 
kept under observation as controls, as in several cases the same lot 
of ticks from untreated cattle was utilized as a control for several lots 
from treated cattle. Reviewing the observations recorded relative to 
the ticks removed from cattle, it may be noted that whereas in many 
of the lots from treated cattle all of the ticks died without ovipositing, 
in most cases some of the ticks deposited eggs, the percentage of ticks 
ovipositing usually being low although in rare instances as high as 
100 per cent (Tables 1 to 7, column 4). In the control lots the 
number of ticks ovipositing was almost always 100 per cent (Tables 
1 to 7, column 8). 

A marked difference is also apparent with reference to the number 
of eggs deposited by ticks from treated and from untreated cattle. 
Ticks from treated cattle which survived to deposit eggs nearly always 
deposited a much smaller number than ticks from untreated cattle 
(Tables 1 to 7, columns 5 and 9). 

Moreover, not only were the eggs deposited by ticks from treated 
cattle less numerous but they rarely hatched. On the other hand in 
only one instance among the control lots did all the eggs fail to hatch 
(Tables 1 to 7, columns 6 and 10). This was due to the lack of proper 
moisture, and the same circumstance explains the rather low per- 
centage of eggs which hatched in several other control lots. In great 
contrast to the high percentage of eggs hatching among those de- 
posited by ticks from untreated cattle, is the fact that out of approxi- 



EFFECTS OF ARSENICAL DIPS ON TICKS. 53 

mately 70 lots of ticks ^ from treated cattle only 4 lots deposited eggs 
wliich hatched. The data concerning these 4 lots of ticks are as 
follows: Three ticks, removed from cattle immediately after spray- 
ing with a dip containing an equivalent of 0.217 per cent arsenic 
trioxid but in which the sodium arsenite had become largely oxidized 
to sodium arsenate, deposited eggs of which 5 per cent hatched 
(experiment No. 12). Twenty out of 48 ticks removed from cattle 
two days after dipping in a dip containing an equivalent of 0.202 per 
cent arsenic trioxid deposited eggs of which 1 per cent hatched (experi- 
ment No. 20), and in the same experiment 10 out of 22 ticks removed 
three days after dipping deposited eggs of which less than 1 per cent 
hatched. The fourth case was that of a tick removed from a calf 
four days after dipping in a dip contaming an equivalent of 0.215 per 
cent arsenic trioxid. This tick deposited numerous eggs about half 
of which hatched (experiment No. 6). Judging from these results it 
would appear that the hatching of eggs deposited by ticks which 
survived treatment with arsenical dips is a rather rare occurrence. 
Furthermore, it has been noted that the larvae from eggs deposited 
by females which have been subjected to arsenical solutions are fre- 
quently in such a weakened condition that they can not emerge from 
the eggshell, or they may become lodged in the opening of the rup- 
tured shell and fail to extricate themselves, or show such slowness 
of movements after emerging as to make one believe that they could 
not effect a successful attachment after reaching a host, a condition 
of the larvae wliich has also been noticed in the case of eggs sub- 
jected to unfavorable conditions, such as a low relative humidity and 
low temperatures. 

The data relative to the ticks removed from cattle after treatment 
and their corresponding controls from untreated cattle given in the 
account of the various experiments are summarized in Tables 1 to 7. 

In part A of each table are given the data relative to ticks from 
treated cattle, and in part B the data relative to ticks from untreated 
cattle, these being removed from their host on corresponding dates 
and kept under the same conditions as those from the treated cattle. 
The data for each lot and its corresponding control are given in the 
same horizontal line. 

Column 1. The figures given in this column refer to the number of 
the experiment to which each lot of ticks belonged. 

Column 2. In this column is given the percentage of arsenic, 
expressed in terms of arsenic trioxid, which was contained in the dip 
used in treating the cattle from which the ticks were removed. 

1 This includes all of the different lots of ticks collected from the treated cattle in the various experiments 
with the exception of experiment No. 5, which is omitted from consideration on account of the fact that the 
dip used contained an imusually low percentage of arsenic. 



54 



AESENICAL DIPS FOR CATTLE TICKS. 



Column 3. In this column is given the number of ticks included in 
each lot removed for observation. 

Column 4. The percentage of ticks in each lot which survived to 
deposit eggs is given in this column. 

Column 5. In this column is given the average number of eggs 
deposited by each tick which survived to deposit eggs. This number 
was determined either by counting or by weighing the eggs and by 
calculation from the weight upon the assumption that one egg aver- 
ages 0.04 milligram in weight. 

Column 6. In this column is given for each lot the percentage of 
eggs hatching. 

Columns 7, 8, 9, 10. The data in these columns refer to ticks from 
untreated cattle and correspond to the data given in columns 3, 4, 5, 
and 6, respectively. 

Table 1. — Results with engorged ticks collected afeiv hoiirs after treatment. 



A. From treated cattle. 


B. From untreated cattle (controls). 


1 


2 


3 


4 


5 


6 


7 


8 


9 


10 


Experi- 


Per cent of 


Number 


Per cent 


Number 


Per cent 


Number 


Per cent 


Number 


Per cent 


ment 
No. 


arsenic in 
dip. 


of ticlis. 


oviposit- 
ing. 


of eggs 
per tick. 


hatching. 


of ticks. 


oviposit- 
ing. 


of eggs 
per tick. 


hatching. 


1 


0.204 


6 


33 


Few. 





8 


100 


Normal. 


95 


2 


.172 


8 


88 


...do 





{ iS 


(?) 
(?) 


(?) 
Normal. 


10 
Over 50. 


3 


.217 


15 











(?) 


(?) 


. .do 


Many. 


6 


.215 


/ '57 
\ 27 


31 


107 





17 


100 


1,316 


97 


37 


252 





1 


100 


1,065 


40 


8 


0. 21.'>- . 234 


/ 46 
I 6 
( 20 


2 
50 
85 


30 

728 
481 







} « 


100 


1,336 


60 


9 


.225 


\ 2 14 


33 
79 


328 
439 






6 


100 


1,083 


25 




f 3.217 


i '\ 


73 


(?) 















100 


(?) 


5 










12 


.234 


/ 37 
\ 2 


16 
100 


Few. 
(?) 






29 


100 


(?) 


40 




[ .222 


/ 59 
I 18 






















13 


.17 


38 


24 


Few. 





{ .5 


(?) 
(?) 


(?) 
Normal. 


10 
Over 50. 


14 


.476 


49 











<25 


96 


316 


12 


If) 


.495 


f "43 
I 19 




21 




81 







1 <22 


96 


505 


50 


20 


.202 


B30 


4 


(?) 





6 36 


(?) 


(?) 


50 


21 


.224 


100 











100 


100 


(?) 









1 Engorged and nearly engorged. 

2 One partially engorged. 

3 Oxidized dip. 



* Partially enuorged. 

6 Twenty partially engorged. 

« Twenty-five partially engorged. 



EFFECTS OF ARSENICAL DIPS ON TICKS, 55 

Table 2. — Results with engorged ticks collected one day after treatment. 



A. From treated cattle. 


B. From untreated cattle (controls). 


1 


2 


3 


4 


5 


6 


7 


8 


9 


10 


Experi- 


Per cent of 


Num- 


Per cent 


Number of 


Per cent 


Num- 


Per cent 


Number of 


Per cent 


ment 


arsenic m 


hcr of 


oviposit- 


eefis per 


hatcli- 


ber of 


oviposit- 


eggs per 


hatch- 


No. 


dip. 


ticlirs. 


ing. 


tick. 


mg. 


ticks. 


ing. 


tick. 


ing. 


6 


0.215 


124 


21 


256 





{ ■; 


100 
100 


1,316 
1,065 


97 
40 


8 


0. 215- . 234 


32 


25 


127 





/ 40 
I 5 


100 
(?) 


1,336 
Numerous. 


60 
98 


9 


.225 


f 15 
\ 10 


80 
40 


609 
322 






] -^ 


100 


921 


10 




2.217 


29 


86 


(?) 





1 








12 


.234 


31 


58 


(?) 





45 


100 


(?) 


75 




.222 


15 


47 


(?) 





1 








14 


.476 


3 12 











M 


100 


853 


75 


16 


.495 


MS 


17 


413 





6 18 


100 


339 


40 



1 Seventeen partially engorged. 

2 Oxidized dip. 

3 Seven partially engorged. 



■" Three partially engorged. 
6 Twelve partially engorged. 
6 Fourteen nearly engorged. 



Table 3. — Engorged ticks collected two days after treatment. 



A. From treated cattle. 


B. From untreated cattle (controls). 


1 


2 


3 


4 


5 


6 


7 


8 


9 


10 


Experi- 


Per cent of 


Num- 


Per cent 


Number of 


Per cent 


Num- 


Per cent 


Number of 


Per cent 


ment 


arsenic in 


ber of 


oviposit- 


eggs per 


hatch- 


ber of 


oviposit- 


eggs per 


hatch- 


No. 


dip. 


ticks. 


ing. 


tick. 


ing. 


ticks. 


ing. 


tick. 


mg. 


1 


0.204 


14 


64 


(?) 





8 


100 


Normal. 


95 


6 


.215 


1 17 


24 


312 





2 8 


100 


1,464 


99 


8 


0. 215- . 234 


6 
f 3 


67 
100 


646 

478 






{ 40 
1 


(?) 
100 


Numerous. 
1,336 


98 
60 


9 


.225 


34 

I «29 


50 
58 


419 
361 






1 " 


100 


2,076 


1 




f I*. 217 


8 


88 


(?) 





1 








12 


\ .234 


12 


50 


(?) 





14 


100 


(?) 


4 




[ .222 


6 


50 


(?) 





1 








14 


.476 


66 











61 


100 


737 


SO 


16 


.495 


<14 


14 


103 




'5 


100 


777 


60 


20 


.202 


/ 48 
\ 8 26 


42 
19 


(?) 
(?) 


1 



1 »14 


100 


(?) 


4 




.224 


j 9 60 


80 


Less than 
normal. 




MO 


100 


Normal. 




21 










1 «10 










•30 


10 


(?) 











I Ten partially engorged. 
» Three partially engorged. 
» Three nearly engorged. 



* Eight nearly engorged. 

5 Oxidized dip. 

6 Nearly engorged. 



' Two partially engorged. 

8 Partially engorged. 

" Some only partially engorged. 



56 



ARSENICAL DIPS FOR CATTLE TICKS. 
Table 4. — Engorged ticks collected three days after treatment. 



A. From treated cattle. 


B. From untreated cattle (controls). 


1 


2 


3 


4 


5 


6 


7 


8 


9 


10 


Experi- 
ment 
No. 


Per cent of 

arsenic in 

dip. 


Num- 
ber of 
ticliS. 


Per cent 
oviposit- 
ing. 


Number of 

eggs per 

tick. 


Per cent 
hatch- 
ing. 


Num- 
ber of 
ticks. 


Per cent 
oviposit- 
ing. 


Number of 

eggs per 

tick. 


Per cent 
hatch- 
ing. 


6 
8 

9 

12 
13 


0.215 
0.215- .234 

.225 

f <.217 
\ .234 
.17 

.495 


19 
9 

1 ' 

[ 3 11 

8 

4 

34 

2 6 


78 
11 

25 
100 

27 
100 

50 
3 

17 


612 

75 

037 

Very few. 

310 

(?) 

(?) 

Few. 

732 
















28 

{ 't 

■ 18 

1 '^ 


100 
100 
(?) 

94 
100 


1,464 

1,336 

Numerous. 

784 
(?) 


99 
60 
98 

2 

1 


16 


\ "' 


100 
100 


1,316 

1,065 


97 

40 


20 


.202 


{ sis 


45 
(?) 


(?) 
(?) 


1 




}■ 6 14 


(?) 


(?) 


10 



1 Four nearly engorged. 

2 Three partially engorged. 
8 Three nearly engorged. 



4 Oxidized dip. 

6 Thirteen partially engorged. 

6 Partially engorged. 



Table 5. — Engorged ticks collected four days after treatment. 



A. From treated cattle. 


B. From untreated cattle (controls). 


1 


2 


3 


4 


5 





7 


S 


9 


10 


Experi- 
ment 
No. 


Per cent of 

arsenic in 

dip. 


Num- 
ber of 
ticlss. 


Per cent 
oviposit- 
ing. 


Number of 

eggs per 

tick. 


Per cent 
hatch- 
ing. 


Num- 
ber of 
ticks. 


Per cent 
oviposit- 
ing. 


Number of 

eggs per 

tick. 


Per cent 
hatch- 
ing. 


6 

9 

12 
20 


0.215 

.225 

2.217 
.202 

. 224 


{ .; 

1 

33 

1 " 

[ U2 


100 
100 


100 


40 




1.400 
933 

(?) 



Less than 

nonnal. 




50 






1 

} ' 

2 
3:1 
15 

4 12 


100 
100 
100 
(?) 
100 




1,787 

1,323 

(?) 
(?) 
(?) 




98 

1 


60 


21 













1 Nearly engorged. 

2 Oxidized dip. 



3 Partinlly engorged. 
■I Less than half grown. 



Table Ck — Engorged ticks collected five days after treatment. 



A. From treated cattle. 


B. From untreated cattle (controls). 


1 


2 


3 


4 


5 


6 


7 


S 


9 


10 


Experi- 
ment 
No. 


Per cent of 

arsenic in 

dip. 


Num- 
ber of 
ticks. 


Per cent 
oviposit- 
ing. 


Number of 

eggs per 

tick. 


Per cent 
hatch- 
ing. 


Num- 
ber of 
ticks. 


Per cent 
oviposit- 
ing. 


Number of 

eggs per 

tick. 


Per cent 
hatch- 
ing. 


2 

20 


0.172 
.202 


5 
1 


20 



200 







{ 't 

13 


(?) 
(?) 
100 


Numerous. 
(?) 
(?) 


Over 50 
10 
95 



1 Two two-thirds engorged. 



EFFECTS OF ARSENICAL DIPS ON TICKS. 
Table 7. — Engorged ticks collected six days after treatment. 



57 



A. From treated cattle. 


B. From untreated cattle (controls). 


1 


2 


3 


•1 


5 


6 




8 


9 


10 


Experi- 
ment 
No. 


Per cent of 

arsenic in 

dip. 


Num- 
ber of 
ticks. 


Per cent 
oviposit- 
ing. 


Number of 

eggs per 

tick. 


Per cent 
hatch- 
ing. 


Num- 
ber of 
ticks. 


Per cent 
oviposit- 
ing. 


Number of 

eggs per 

tick. 


Per cent 
hatch- 
ing. 


20 


0.202 
.224 


1 1 



25 






Less tlian 

normal. 

















2 12 

7 


100 



(?) 






21 







1 Not more than half grown. 



2 Some not fully engorged. 



The effects obtained when engorged ticks are taken from untreated 
cattle and immersed in arsenical dips for a couple of minutes are 
very much the same as those observed when the ticks are removed 
from cattle after treatment. (See Table 8.) Sixteen lots, containing 
from 15 to 123 ticks each, were thus treated. In 5 of the lots none 
of the ticks oviposited, in the remainder 3 to 100 per cent deposited 
eggs. In each of the control lots, composed of 4 to 105 ticks each, 
95 to 100 per cent of the ticks oviposited. The number of eggs 
deposited by each treated tick which survived to oviposit averaged 
much less than in the case of the untreated ticks. In the case of 
only two lots of treated ticks did any of the eggs hatch. These two 
lots were treated with a neutral and alkaline solution, respectively, 
of sodium arsenate equivalent to 0.22 per cent arsenic trioxid, and 
only 1 and 2 per cent, respectively, of the eggs hatched. In the con- 
trol lot 99 per cent of the eggs hatched. In view of the close corre- 
spondence between the results of the experiments in which engorged 
ticks w^ere kept under observation after their removal from treated 
cattle and those in which engorged ticks were removed from untreated 
cattle and kept under observation after immersion for a short time 
in arsenical dips, it is evident that experiments of the latter Idnd are 
useful in that they furnish an indication of the efficacy of arsenical 
dips so far as engorged or nearly engorged ticks are concerned. 

The arrangement of Table 8 is similar to that of Tables 1 to 7, 
the data relative to the dipped ticks being given in part A and the 
data relative to the undipped ticks in part B. The various columns 
in the table are likewise of similar sio-nificance. 



58 ARSENICAL DIPS FOR CATTLE TICKS. 

Table 8. — Results with engorged ticks dipped in the laboratory. 



A. Dipped ticks. 


B. Undipped ticks (controls). 


1 


2 


3 


4 


5 


6 


7 


8 


9 


10 


Experi- 
ment 
No. 


Per cent of 

arsenic in 

dip. 


Num- 
ber of 
ticlis. 


Per cent 
oviposit- 
ing. 


Nimiber 
of eggs 
per tick. 


Per cent 
hatching. 


Nimi- 
ber of 
ticks. 


Per cent 
oviposit- 
ing. 


Number 

of eggs 

per tick. 


Per cent 
hatching. 


4 
7 


0. 213 

.215 

f 1.217 
.24 

1.217 
.24 

1.217 
.24 
.24 

.476 

.495 
/ 2.22 
1 3.22 
/ 4.22 
t .22 


123 
f 15 
i 51 
10 
16 
15 
15 
22 
22 
21 

46 

59 
20 
20 
22 
22 


82 



13 
7 

60 


14 


14 

4 

3 
95 
100 
86 




712 



Few. 
12 

Few. 


Few. 


Few. 

98 
150 
(?) 
(?) 
(?) 


















1 
2 




105 
8 
40 

} ■« 


100 
100 
100 

100 


3,189 
1,464 
1,336 

(?) 


99 
99 
60 

40 


11 










15 
17 
18 

19 


} - 

21 
1 20 

} - 


95 

95 

98 
100 
98 

100 
100 


(?) 

(?) 
1,443 
853 
1,195 

(?) 
(?) 


25 

75 
98 
75 
97 

99 

1 



1 Oxidized dip. 

2 Sodium arsenate (neutral). 



3 Sodium arsenate (alkaline). 
* Sodium sulpharsenite. 



No more is known as to the exact way in wliicli the poisonous 
action of arsenic takes effect upon the eggs of ticks than is known 
as to the way in which it takes effect upon the ticks themselves. 
The fact that the eggs have been injured becomes apparent soon after 
deposition, sometimes immediately. Those wliich have been injuri- 
ously affected are then readily distinguished by their dark color and 
shriveled condition. The two series of photographs given in Plates 
I to VI, in which the appearance of treated and untreated ticks may 
be compared, show very strikingly some of the effects of arsenical 
dips upon ticks and their eggs. 

Summing up the numerous observations which have been made 
as to the effects of arsenical dips upon engorged, partially engorged, 
and young female ticks, it will be noted (1) that cattle were generally 
free from engorged ticks within a week after treatment ; (2) that of the 
ticks which were present in the engorged stage at the time of treatment 
or which subsequently reached the engorged stage, only a few, as a rule, 
deposited eggs; (3) that the number of eggs deposited was much 
less than normal; and (4) that very few of the eggs hatched. 



MALE TICKS. 



Very few male ticks were found alive on cattle later than a day or 
two after treatment, and it is probable that most of these were ticks 
which were in the nymphal stage at the time of treatment. It may 
therefore be concluded that arsenical dips are highly efficacious so 
far as the destruction of male ticks is concerned. 



EFFECTS OF ARSENICAL DIPS ON TICKS. 59 



NYMPHS AND LARV^,. 



It was found in the experiments with arsenical dips that the vast 
majority of nymphs were killed by a single treatment. In several 
experiments, however, some of the nymphs survived and afterwards 
molted. Supplementing the observations made on nymphs in situ 
on cattle after treatment, observations were made on nymphs removed 
from their hosts subsequent to treatment after the lapse of varying 
periods of time. (See Table 9.) These observations showed that 
in the case of 12 lots none of the nymphs molted; and that in the 
case of four lots 8 to 50 per cent molted. Nymphs removed from 
untreated cattle and kept under the same conditions, as controls, 
usually molted, 10 to 100 per cent in nine lots, only one lot being 
collected in which all the nymphs failed to molt. 

In Table 9 are given data, summarized from the various experi- 
ments, relative to the molting of nymphs removed from cattle after 
varjdng periods of time subsequent to treatment, as compared with 
the molting of nymphs removed on corresponding dates from untreated 
cattle. 

Part A refers to nymphs from treated cattle, and part B to nymphs 
from untreated cattle removed on corresponding dates and kept 
under similar conditions. 

Column 1. In this column is given the number of the experiment 
to wliich each lot of nymphs belonged. 

Column 2, In this column is given the percentage of arsenic, 
expressed in terms of arsenic trioxid, wliich was contained in the 
dip used in treating the cattle from which the ticks were removed. 

Column 3. The figures in this column refer to the number of days 
which elapsed from the time the cattle were treated until the nymphs 
were removed. 

Column 4. In tliis column is given the number of nymphs included 
in each lot removed for observation. 

Column 5. The percentage of nymphs which molted subsequent 
to removal from their host is given in this column. 

Column 6, In this column is given the number of nymphs in each 
lot removed from untreated cattle. 

Column 7. The percentage of nymphs which molted subsequent 
to their removal from untreated cattle is given in this column. 



60 ARSENICAL DTPS POR CATTLE TICKS. 

Table 9. — Results with nymphs collected from dipped and undipped cattle. 



A. From treated cattle. 


B. From untreated 
cattle (controls). 


1 


2 


3 


4 


5 


fi 


7 


Experiment No. 


Per cent 

of arsenic 

in dip. 


Number 
of days. 


Number 
of ticks. 


Per cent 
which 
molted. 


Number 
of ticks. 

14 


Per cent 
which 
molted. 


1 


0.204 

0.172 
0.217 
0.17 

0.202 
0.224 


{ ? 

{ 1 


f 14 hours. 


2 
3 
4 
5 
fi 
2 
4 
6 


4 

■ 13 
(i9 

7 

6 
10 

9 
12 
17 
41 
54 
40 

1 
15 
15 

4 


50 
8 



33 










13 



79 






2 .. 


} - 

4 
25 


84 


3 


75 


13 


84 








20 
2 


95 
100 




42 
12 






64 
83 


21 


20 
15 
4 


10 
20 








No instance was observed in any of the experiments of the survival 
of ticks in the larval stage after a single treatment with an arsenical 
dip. Wliile the possibility of such an occurrence must be admitted, 
it seems certain that the survival of larvae after treatment with an 
arsenical dip of proper strength would be very exceptional, and for 
practical purposes it seems safe to assume, until evidence can be 
obtained to the contrary, that arsenical dips are entirely efficacious 
so far as concerns ticks in the larval stage. 

THE PROTECTIVE ACTION OF ARSENICAL DIPS. 

Little evidence has been obtained as to the degree of protection 
against reinfestation afforded by arsenical dips or as to the length of 
time after treatment that such protective action continues. It seems, 
however, that cattle are pi»otected from reinfestation, at least to some 
extent, during several days after treatinent. The results obtained by 
Watldns-Pitchford with regard to the accumulation of arsenic in the 
skin and the toxicity of regularly treated animals, already referred to, 
would seem to show that an arsenical dip may protect cattle consid- 
erably against reinfestation. Owing to the uncertainty as to this point, 
however, it is unsafe to place any reliance upon the protective action 
of arsenical dips, and it should be assumed that treated cattle are 
liable to reinfestation if exposed at any time after the arsenical solu- 
tion has become dry upon their bodies. 



DISCUSSION OF RESULTS OF EXPERIMENTS. 61 

PRACTICAL SIGNIFICANCE OF RESULTS OF EXPERIMENTS WITH 

ARSENICAL DIPS. 

In considering the practical application of the results of the experi- 
ments with arsenical dips, it should first of all be noted that although 
arsenic has a marked effect on all stages of the tick, none of the arsen- 
ical dips tested has proved sufficiently efficacious to insure a tick-free 
condition of cattle by means of a single application of the dip. As we 
know them at present, therefore, arsenical dips must be considered as 
falling short of the ideal of perfect elTicacy. 

The question then arises whether with their admitted imperfections 
arsenical dips may be used with advantage in the eradication of ticks. 
This question may be unhesitatingly answered in the affirmative. 
Arsenical dips are undoubtedly of very great value in tick eradica- 
tion, and all things considered no better dip for the destruction of 
ticks has yet been discovered. This has been demonstrated not only 
by experimental work, but also by the results obtained from an exten- 
sive practical use of arsenical dips by many owners of live stock in 
Texas, Oklahoma, and California. 

The practical application of the results of the experiments with 
arsenical dips may be considered under the following heads : (1) Com- 
position of the dip; (2) method of application; (3) number and fre- 
quency of applications ; (4) handling the cattle. 

COMPOSITION OF THE DIP. 

The investigations thus far carried out have not been extensive 
enough to enable a definite statement to be made as to the minimum 
percentage of arsenic required to give an arsenical dip a sufliciently 
high degree of efhcacy to make it of practical value. Moreover, it is 
probable that a stronger dip will be necessary to obtain satisfactory 
results under some conditions than under others, and it is probable 
also that in many cases a rather weak dip may be used to advantage 
when a stronger dip would be undesirable on account of possible inju- 
rious effects on cattle, as, for example, in the case of repeated treat- 
ments during very hot weather. 

The experiments indicate that dips containing as high as 0.24 per 
cent arsenic (reckoned as arsenic trixoid) may be used without unduly 
injuring cattle. It has been assumed that this is the maximum 
strength at which dips containing arsenic in the form of sodium arse- 
nite or potassium arsenite may be used without too great risk of injury. 
In view of the fact that in one experiment (No. 5) an arsenical dip con- 
taining somewhat less than an equivalent of 0.2 per cent proved less 
efficacious than dips in other experiments which contained an equiv- 
alent of approximately 0.2 per cent or more of arsenic trioxid, 0.2 per 
cent was selected as an arbitrary minimum limit. The mean between 



62 ABSENICAL DIPS FOR CATTLE TICKS. 

the minimum and maximum limits, or 0.22 per cent, may therefore 
be taken as an arbitrary standard, and a dip to have the maximum 
degree of efficacy, so far as this may be attained without great risk 
of injury to cattle, should not deviate more than very slightly above 
or below this standard of 0.22 per cent. 

The arsenical dips commonly used and with special reference to 
which most of the experimental work has been done are based on a 
modification of Dr. Mayo's formula given in the introduction of the 
present article. Directions for preparing such a dip so that it will 
conform to the standard which has been selected are as follows: 

In preparing each 500 gallons of the standard arsenical solution there shall be used 
10 pounds of finely powdered white arsenic containing not less than 99 per cent of 
arsenic trioxid, 25 pounds of sal soda, and 1 gallon of pine tar. The arsenic and sal 
soda shall be boiled together in not less than 25 gallons of water for fifteen minutes, or 
longer if necessary to effect complete solution of the arsenic. Before the pine tar is 
added, the temperature of the solution shall be reduced to 140° F. This may be done 
by the addition of cold water. The pine tar shall then be added in a small stream 
while the solution is thoroughly stirred, after which the solution shall be immediately 
diluted with clear water sufficient to make 500 gallons of dip. 

The coohng of the arsenic and sal soda solution before the addition 
of the pine tar is important, as otherwise an imperfect mixture having 
a curdled appearance is likely to result. 

It has already been noted that the quantity of sal soda used in the 
above formula is in excess of the amount actually needed to combine 
with all the arsenic, but until it can be shown that the efficacy of the 
dip in no way depends upon the presence of this excess of soda, the 
proportionate amount of sal soda should not be reduced. 

In cases wherein it is considered expedient to use a weaker dip the 
amount of arsenic may be reduced to 8 pounds per 500 gallons of 
dip, but for all official dippings the standard amount of 10 pounds 
to 500 gallons is required. 

METHOD OF APPLICATION. 

There are two practicable methods of applying arsenical dips, 
namely, by spraying and by dipping. 

Spraying is not practicable except in the case of very small herds, 
unless a spraying machine is used. Spraying machines, however, 
have proved less satisfactory than dipping vats, and it is therefore 
preferable to use a dipping vat whenever more cattle are to be treated 
than it is practicable to treat by means of hand spray pumps. Hand 
spraying is not only more tedious than dipping, but it is also less 
efficacious, as there is not the same certainty of getting a thorough 
application of the dip even when the greatest care is used. Conse- 
quently the dipping vat is much more reliable than the spray pump. 
It is also more economical whenever more than a very few animals 
are to be treated. 



DISCUSSION OF RESULTS OF EXPEEIMENTS. 63 

A dipping vat for cattle should be large enough to afford a bath 
at least 5J feet in depth, and unless the cattle when dipped are held 
in the bath, the vat should measure at least 40 feet in length at the 
surface of the dip. If a shorter vat is used the cattle should be 
held in the bath at least 15 seconds — half a minute would be better — 
otherwise they are liable to get through the bath without being 
thoroughly wet to the skin, particularly if the hair is long, A steep 
slide at the entrance of the vat is desirable in order to insure a plunge 
which will carry the cattle entirely under the surface of the bath.^ 

NUMBER AND FREQUENCY OF APPLICATIONS. 

From the data obtained in the experimental work it appears that 
one treatment with an arsenical dip is insufficient to free cattle from 
ticks. Subsequent to dipping, ticks continue to reach engorge- 
ment and fall from the cattle for several days and a few nymphs are 
liable to survive, molt, and possibly continue their development to 
the engorged stage. On the other hand, no instance has been 
recorded in which a tick survived and reached fertile maturity after 
two thorough applicatons of an arsenical dip given 7 to 10 clays 
apart, and no larvae have been observed that have survived a single 
treatment. The results of the experiments therefore show that cattle 
may be freed from ticks by two treatments with an arsenical dip. 

Although the possibility of ticks surviving two treatments and 
maintaining the ability to reproduce is always present, the experi- 
mental work shows that such an occurrence must be very rare, pro- 
vided the treatments are thorough, and it is therefore proper to 
assume, as a working basis, that two treatments are entirely effica- 
cious. Accordingly it may be stated as a tentative conclusion that 
after two thorough treatments cattle may be placed on uninfested 
ground with practically no danger of carrying with them any ticks 
capable of perpetuating the species. In practice, therefore, when 
cattle are to be treated for the purpose of ridding them of ticks so 
that they may be put in uninfested pastures or other tick-free places, 
they should be dipped twice with an interval of 7 to 10 days between 
dippings, using a full-strength arsenical dip. 

When cattle are to continue occupying the same pasture or range 
the question of the number and frequency of treatments is somewhat 
different. In this case the rule would be to give repeated treatments 
at intervals of not over three weeks. Usually more than three weeks 
and rarely less than this time is required for larval ticks after reach- 
ing a host to complete their development to the engorged stage. 
Hence if cattle were treated every three weeks practically all of the 
ticks which they picked up in the meantime would be subjected to 

1 The Bureau of Animal Industry is prepared to furnish plans and specifications for dipping vats to 
persons contemplating the construction of vats. 



64 ARSENICAL DIPS FOR CATTLE TICKS. 

treatment. Scarcely any would escape and deposit eggs, and when 
it is considered that the average number of eggs deposited by each 
tick surviving treatment would be less than normal, and that only 
a small proportion would hatch, it is evident that the amount of 
infestation of cattle and pastures would greatly and rapidly diminish. 
Practical experience has demonstrated that complete eradication 
may be accomplished in this way, the probable explanation being 
that even if ticks occasionally survive dipping the number is reduced 
below the minimum necessary to insure the survival of the species. 
In other words, in those localities where ticks are established, their 
fecundity is sufficient for the perpetuation of the species under 
ordinary conditions, but if the vast majority of individuals that find 
a host are destroyed, a point is soon reached in the numerical reduc- 
tion below which it is impossible for the species to maintain itself. 
No set rule can be formulated at present as to the number of times 
it will be necessary to repeat the treatment with the arsenical dip 
to bring about eradication, but a general rule would be to continue 
the treatment until the ticks had apparently disappeared, then dis- 
continue it, and if at any time ticks are again observed, resume the 
treatment, keeping always on the lookout for signs of ticks, just as 
a physician, in the case of diseases liable to reappear when appa- 
rently cured, watches for symptoms indicating a recurrence of the 
malady. 

HANDLING THE CATTLE. 

Cattle should not be treated with arsenical dips when tired or 
thirsty, and after treatment should not be allowed to drain in places 
where the drippings from their bodies will form pools which they 
may drink, or where grass or fodder will become soaked with the 
dip. For a week or so after treatment, especially in hot weather, 
cattle should not be driven hard or allowed to run or become over- 
heated. After treatment cattle may, however, be safely shipped by 
rail, even though they are loaded as soon as their bodies become dry. 

When cattle are to be freed from ticks by two treatments a special 
arrangement of the dipping plant and yards for handling the cattle 
is necessary, so that after the second dipping they will not be exposed 
to reinfestation. Certain yards and the alleyways leading to them 
from the draining pen must be reserved exclusively for cattle which 
have been twice dipped. These yards and alleyways must be free 
from infection and must not be used for any cattle except those 
which have been twice dipped or are known to be free from ticks. 
For several days after the first dipping cattle are likely still to harbor 
ticks able to reproduce, hence it is unsafe to place them in yards or 
pastures which it is desirable to keep free from infection, and as the 
second dipping will destroy any larvae which they may pick up in the 



DISCUSSION" OF RESULTS OF EXPEBIMENTS. 



66 



meantime, cattle should be kept between dippings in })laces which kro 
either definitely known to be infested, or which it is not desired to 
be kept free from ticks. After the second dipping, however, cattle 
must be guarded from exposure to infection, hence from the time 
they leave the draining pens they must not pass over or occupy any 
places infested with ticks. In order thus to handle cattle either two 
dipping vats will be required, or, if the same vat is used for both 
dippings, some arrangement must be made whcreliy cattle may be 



cHure TO 



'^ (MC/rS TV 



i/ 






Fig. 1. — Plan of draining pen for cattle after dipping. 

brought fi'om the draining pens to their respective yards after the 
first and second dippings by entirely distinct routes. This may be 
readily done when a single drainmg pen is used if the two alleyways 
for once-dipped and twice-dipped cattle, respectively, lead away in 
difl'erent directions from the drainmg pen. If, however, the common 
type of double draining pen is used it will be necessaiy to add a 
third section (as shown in the plan) in order that separate routes for 
once-dipped and twice-dipped cattle may be provided for. 



o 



10407°— Bull. 144—12- 



cvl'r}.-t i 



IB N '12 



